Curable polyvinyl benzyl compound and process for producing the same

ABSTRACT

A curable polyvinyl benzyl compound represented by the following general formula (1)  
                 
 
wherein R 1  represents a C 2-20  organic group, R 2  represents a hydrogen atom, etc., x is an integer of 0 to 4, and n is an integer of 0 to 2. The compound is obtained by reacting a fluorene compound with a vinylbenzyl halide in the presence of an alkali.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 10/954,214filed Oct. 1, 2004, which is a Continuation-In-Part of U.S. applicationSer. No. 10/474,453 filed Oct. 8, 2003, which is the National Stage ofPCT/JP02/02851 filed on Mar. 25, 2002.

TECHNICAL FIELD

The present invention relates to a compound which provides a curedproduct having high heat resistance, low water absorption and excellentdielectric properties which are required for organic insulatingmaterials for use in electronic equipment such as communicationequipment and to a process for producing the same. More specifically,the present invention relates to a curable polyvinyl benzyl compoundobtained by reacting a fluorene compound with a vinylbenzyl halide, aprocess for producing the same, and a curable resin composition and acured resin obtained by using the same. Further, the present inventionrelates to a substrate, a prepreg and a metal foil having a resin, allof which have excellent dielectric properties at a high-frequency range,in particular, a low dielectric dissipation factor, and high heatresistance.

BACKGROUND ART

Along with recent progress in electronic technology, materials having alow dielectric constant and a low dielectric dissipation factor are nowin demand as materials of parts for use in computers and mobilecommunication equipment. To satisfy this demand, various materials arebeing developed. The materials include, for example,polybenzocyclobutene (R. A. Kirchhoff et al., Macromol. Symp. 54/55, 531(1992)), fluorinated polybiphenylene ether (JP 10-74751 A),polyphenylene compound having a heterocyclic side chain (JP 9-278879 A),polyfumarate (JP 9-208697 A), polynorbornene (JP 5-214079 A),polyquinoxaline (JP 2705799 B), fluorinated polyquinoline (JP 6-500591A), side chain allyl group-substituted polyphenylene ether (JP 64-69628A, JP 4-183707 A, and JP 6-207096 A), and polyphenylene ether whoseterminal is blocked with an allyl group or a propargyl group (JP 7-51625B).

However, the above materials proposed in the prior art have variousproblems such as a low crosslinking density and a large linear expansioncoefficient; low chemical resistance; poor tenacity; a large number ofcomplicated steps required for the production of a resin from rawmaterials; and the need for a special solvent for shaping. Therefore,they have not been put to practical use yet.

The inventors of the present invention have proposed a vinylbenzyl ethercompound which has low water absorption over a wide temperature rangeand a wide frequency range, a low dielectric constant and a lowdielectric dissipation factor and satisfies the current strictrequirements for electronic materials (JP 9-31006 A). This vinylbenzylether compound can be synthesized by reacting an aromatic compoundhaving a hydroxyl group with a vinylbenzyl halide in a polar solvent inthe presence of an alkali, or in a water/organic solvent mixed solutionin the presence of a phase-transfer catalyst.

However, the requirements for dielectric properties of electronicmaterials are becoming more and more demanding. Next-generationcommunication devices have begun to appear, which require, inparticular, a low dielectric dissipation factor, which cannot besatisfied even by the above vinylbenzyl ether compound.

It is therefore an object of the present invention to provide apolyvinyl benzyl compound which provides a cured product having highheat resistance, low water absorption, a low dielectric constant and alow dielectric dissipation factor, a process for producing the same, acurable resin composition comprising the same, and a cured resinobtained by curing said composition.

It is another object of the present invention to provide a substrate,prepreg and metal foil having a resin all of which have excellentdielectric properties over a high frequency range, in particular, a lowdielectric dissipation factor, and high heat resistance.

DISCLOSURE OF THE INVENTION

The invention according to claim 1 relates to a curable polyvinyl benzylcompound represented by the following general formula 1:

(wherein R¹ is a divalent organic group having 2 to 20 carbon atoms, R²is at least one organic group selected from the group consisting of ahydrogen atom, a halogen atom, an alkyl group, an alkoxy group and athioalkoxy group having 1 to 5 carbon atoms, which may be the same ordifferent, and an aryl group, where x is an integer of 0 to 4, and n isan integer of 0 to 20).

The invention according to claim 2 relates to a process for producing acurable polyvinyl benzyl compound according to claim 1, characterized byreacting one fluorene compound or two or more fluorene compoundsrepresented by the following general formula 2 and a vinylbenzyl halidein the presence of an alkali:

(wherein R² is at least one organic group selected from a groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxygroup and a thioalkoxy group having 1 to 5 carbon atoms, which may bethe same or different, and an aryl group, where x is an integer of 0 to4).

The invention according to claim 3 relates to a process for producing acurable polyvinyl benzyl compound according to claim 1, characterized byreacting one fluorene compound or two or more fluorene compoundsrepresented by the following general formula 2, a vinylbenzyl halide anda dihalomethyl compound having 2 to 20 carbon atoms in the presence ofan alkali:

(wherein R¹ is at least one organic group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, an alkoxygroup and a thioalkoxy group having 1 to 5 carbon atoms, which may bethe same or different, and an aryl group, where x is an integer of 0 to4).

The invention according to claim 4 relates to the process for producinga curable polyvinyl benzyl compound according to claim 2 or 3, in whichvinylbenzyl halide is at least one selected from the group consisting ofm-vinylbenzyl chloride and p-vinylbenzyl chloride.

The invention according to claim 5 relates to the process for producinga curable polyvinyl benzyl compound according to claim 3, in which anequivalent ratio of a halomethyl group of the vinylbenzyl halide to thehalomethyl group of the dihalomethyl compound having 2 to 20 carbonatoms is 1.0/0 to 0.1/0.9.

The invention according to claim 6 relates to the process for producinga curable polyvinyl benzyl compound according to any one of claims 2 to5, in which the reaction is carried out in the presence of an aproticpolar solvent and/or a phase-transfer catalyst.

The invention according to claim 7 relates to a curable resincomposition prepared by mixing a curable polyvinyl benzyl compoundaccording to claim 1 with a monomer, an oligomer and/or a polymer whichis copolymerizable with said compound.

The invention according to claim 8 relates to a cured resin obtained bycuring a curable polyvinyl benzyl compound according to claim 1.

The invention according to claim 9 relates to a cured resin obtained bycuring a curable resin composition according to claim 7.

The invention according to claim 10 relates to a high-frequencysubstrate obtained by curing a curable polyvinyl benzyl compoundaccording to claim 1.

The invention according to claim 11 relates to a high-frequencysubstrate obtained by curing a curable resin composition according toclaim 7.

The invention according to claim 12 relates to a prepreg obtained byimpregnating a curable resin composition according to claim 7 with afiber material.

The invention according to claim 13 relates to a high-frequencysubstrate obtained by heating and pressurizing either a single prepregaccording to claim 12 or a laminate of the prepregs according to claim12.

The invention according to claim 14 relates to a metal-linedhigh-frequency substrate obtained by placing a metal foil onto either orsingle prepreg according to claim 12 or a laminate of the prepregsaccording to claim 12, through heating and pressurizing.

The invention according to claim 15 relates to a metal foil having aresin obtained by applying a curable resin composition according toclaim 7 to a metal foil to be integrated.

The invention according to claim 16 relates to a multi-layer laminatesubstrate characterized by including a curable resin compositionaccording to claim 7 applied to a conductive layer, which is polymerizedand cured, and a conductive layer formed on a cured product.

The invention according to claim 17 relates to a curable vinylbenzylcompound represented by the following general formula 3:

(wherein, R³, R⁴, and R⁵ each represent a group selected from the groupconsisting of a vinylbenzyl group, a hydrogen atom, an alkyl group,alkoxy group, and thioalkoxy group each having 1 to 5 carbon atoms,which may be the same or different, and an aryl group; at least one ofR³, R⁴, and R⁵ is a vinylbenzyl group; and R⁶ represents at least onegroup selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group, alkoxy group, and thioalkoxy group each having 1to 5 carbon atoms, which may be the same or different, a thioaryloxygroup, and an aryl group).

The invention according to claim 18 relates to a curable vinylbenzylcompound represented by the following general formula 4:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group; R⁷represents a divalent organic group having 2 to 20 carbon atoms; R⁸represents a group selected from the group consisting of a vinylbenzylgroup, a hydrogen atom, an alkyl group, alkoxy group, and thioalkoxygroup each having 1 to 5 carbon atoms, which may be the same ordifferent, and an aryl group; at least one R⁸ is a vinylbenzyl group;and a, b, and c each represent an integer of 0 to 20).

The invention according to claim 19 relates to a curable vinylbenzylcompound obtained by reacting at least one indene compound representedby the following general formula 5, a fluorene compound, a vinylbenzylhalide, and a dihalomethyl compound having 2 to 20 carbon atoms in thepresence of an alkali:

(wherein, R represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

The invention according to claim 20 relates to a process for producingthe curable vinylbenzyl compound according to the seventeenth aspect ofthe present invention, including reacting at least one indene compoundrepresented by the following general formula 5 and a vinylbenzyl halidein the presence of an alkali:

(wherein, a definition of R⁶ is the same as that described above).

The invention according to claim 21 relates to a process for producingthe curable vinylbenzyl compound according to claim 18, includingreacting at least one indene compound represented by the followinggeneral formula 5, a vinylbenzyl halide, and a dihalomethyl compoundhaving 2 to 20 carbon atoms in the presence of an alkali:

(wherein, a definition of R⁶ is the same as that described above).

The invention according to claim 22 relates to a process for producing acurable vinylbenzyl compound according to claim 20 or 21, in which thevinylbenzyl halide is at least one of m-vinylbenzyl chloride andp-vinylbenzyl chloride.

The invention according to claim 23 relates to a process for producing acurable vinylbenzyl compound according to claim 21 or 22, in which anequivalent ratio of a halomethyl group of the vinylbenzyl halide to ahalomethyl group of the dihalomethyl compound having 2 to 20 carbonatoms is adjusted to 0.9:0.1 to 0.1:0.9 for a reaction.

The invention according to claim 24 relates to a process for producing acurable vinylbenzyl compound according to any one of claims 20 to 23, inwhich the reaction is carried out in the presence of an alkali and inthe presence of at least one of an aprotic polar solvent and aphase-transfer catalyst.

The invention according to claim 25 relates to a curable resincomposition prepared by mixing the curable vinylbenzyl compoundaccording to any one of claims 17 to 19 with a compound which iscopolymerizable with the curable vinylbenzyl compound.

The invention according to claim 26 relates to a cured resin obtained bycuring the curable vinylbenzyl compound according to any one of claims17 to 19.

The invention according to claim 27 relates to a cured resin obtained bycuring the curable resin composition according to claim 25.

The invention according to claim 28 relates to a high-frequencysubstrate obtained by polymerizing and curing a polymerizablecomposition, in which the polymerizable composition contains a fluorenecompound having at least one polymerizable unsaturated group in amolecule (except for a case where all of the polymerizable unsaturatedgroups are vinylbenzyl groups).

The invention according to claim 29 relates to a high-frequencysubstrate according to claim 28, in which the fluorene compound containsone of: at least one of an allyl group and a propargyl group as apolymerizable unsaturated group; and at least one polymerizableunsaturated group and a vinylbenzyl group.

The invention according to claim 30 relates to a high-frequencysubstrate obtained by polymerizing and curing a polymerizablecomposition, in which the polymerizable composition contains an indenecompound having at least one polymerizable unsaturated group in amolecule.

The invention according to claim 31 relates to a high-frequencysubstrate according to claim 30, in which the polymerizable unsaturatedgroup is at least one group selected from a vinylbenzyl group, an allylgroup, and a propargyl group.

The invention according to claim 32 relates to a high-frequencysubstrate obtained by polymerizing and curing a polymerizablecomposition, in which the polymerizable composition contains a fluorenecompound having at least one polymerizable unsaturated group in amolecule and an indene compound having at least one polymerizableunsaturated group in a molecule.

The invention according to claim 33 relates to a high-frequencysubstrate according to claim 29, in which: the fluorene compound is atleast one compound represented by the following general formula 6; andthe polymerizable composition is a compound obtained by reacting thefluorene compound, a halogen compound having at least one polymerizableunsaturated group selected from the group consisting of a vinylbenzylhalide, an allyl halide, and a propargyl halide, and a dihalomethylcompound having 2 to 20 carbon atoms in the presence of an alkali:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

The invention according to claim 34 relates to a high-frequencysubstrate according to claim 31, in which: the indene compound is atleast one compound represented by the following general formula 5; andthe polymerizable composition contains a compound obtained by reactingthe indene compound, a halogen compound having at least onepolymerizable unsaturated group selected from the group consisting of avinylbenzyl halide, an allyl halide, and a propargyl halide, and adihalomethyl compound having 2 to 20 carbon atoms in the presence of analkali:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

The invention according to claim 35 relates to a high-frequencysubstrate according to claim 32, in which: the fluorene compound is atleast one compound represented by the following general formula 6; theindene compound is at least one compound represented by the followinggeneral formula 5; and the polymerizable composition is a compoundobtained by reacting the fluorene compound, the indene compound, ahalogen compound having at least one polymerizable unsaturated groupselected from the group consisting of a vinylbenzyl halide, an allylhalide, and a propargyl halide, and a dihalomethyl compound having 2 to20 carbon atoms in the presence of an alkali.

The invention according to claim 36 relates to a high-frequencysubstrate according to any one of claims 33 to 35, in which anequivalent ratio of a halomethyl group of the halogen compound having apolymerizable unsaturated group to a halomethyl group of thedihalomethyl compound having 2 to 20 carbon atoms is 0.9/0.1 to 0.1/0.9.

The invention according to claim 37 relates to a high-frequencysubstrate according to claim 28, in which the polymerizable compositionis a composition prepared by mixing a fluorene compound having at leastone polymerizable unsaturated group in a molecule and a compound whichis copolymerizable with the fluorene compound.

The invention according to claim 38 relates to a high-frequencysubstrate according to claim 30, in which the polymerizable compositionis a composition prepared by mixing an indene compound having at leastone polymerizable unsaturated group in a molecule and a compound whichis copolymerizable with the indene compound.

The invention according to claim 39 relates to a prepreg obtained byimpregnating a fiber material with the polymerizable compositionaccording to any one of claims 28, 30, 32, 33, 34, 35, 37 and 38.

The invention according to claim 40 relates to a prepreg according toclaim 39, in which the fiber material is a glass cloth.

The invention according to claim 41 relates to a high-frequencysubstrate obtained by heating and pressurizing one of a single prepregaccording to claim 39 or 40 and a prepreg laminate.

The invention according to claim 42 relates to a metal-linedhigh-frequency substrate obtained by placing a metal foil onto one of asingle prepreg according to claim 39 or 40 and a prepreg laminate, andheating and pressurizing the whole.

The invention according to claim 43 relates to a metal foil having aresin obtained by applying the polymerizable composition according toany one of claims 28, 30, 32, 33, 34, 35, 37 and 38 to a metal foil andintegrating the polymerizable composition and the metal foil.

The invention according to claim 44 relates to a multi-layer laminatesubstrate including: a cured product prepared by applying thepolymerizable composition according to any one of claims 28, 30, 32, 33,34, 35, 37 and 38 to a conductive layer, and polymerizing and curing thecomposition; and a conductive layer provided on the cured product.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail hereinafter.

A first curable vinylbenzyl compound of the present invention isobtained by reacting one fluorene compound or two or more fluorenecompounds represented by the above general formula 2 with a vinylbenzylhalide and optionally a dihalomethyl compound having 2 to 20 carbonatoms in the presence of an alkali. The reaction can be carried out inaccordance with conditions for a known vinylbenzylation reaction. Thevinylbenzylation reaction is described, for example, by L. J. Mathias etal. in J. Polym. Sci., Part B; 36, 2869 (1998) and J. Polym. Sci., PartA; 35, 587 (1997), and by C. J. Kelly et al. in J. Chem. Res. (S), 446(1997).

Examples of the fluorene compound used in the present invention includefluorene compounds whose fluorene and aromatic ring parts may besubstituted by an alkyl group, alkoxy group, thioalkoxy group or arylgroup as represented by the above general formula 2. They may be usedalone or in combination of two or more compounds.

Examples of the vinylbenzyl halide used in the present invention includem-vinylbenzyl chloride, p-vinylbenzyl chloride, m-vinylbenzyl bromideand p-vinylbenzyl bromide. They may be used alone or in combination oftwo or more compounds. Of these, m-vinylbenzyl chloride andp-vinylbenzyl chloride are preferred.

The dihalomethyl compound used in the present invention is a compoundhaving two —CH₂X (where X is a halogen atom) groups in the molecule and2 to 20 carbon atoms, preferably 2 to 16 carbon atoms. Examples of thedihalomethyl compound include halogenated alkyls such as1,2-dichloroethane, 1,2-dibromoethane, 1,3-dichloropropane,1,3-dibromopropane, 1,4-dichlorobutane and 1,4-dibromobutane, andcompounds such as o-xylylene dichloride, m-xylylene dibromide,p-xylylene dibromide, 4,4′-bis(chloromethyl)biphenyl,4,4′-bis(chloromethyl)diphenyl ether, 4,4′-bis(chloromethyl)diphenylsulfide, 2,6-bis(bromomethyl)naphthalene,1,8-bis(bromomethyl)naphthalene and 1,4-bis(chloromethyl)naphthalene.They may be used alone or in combination of two or more compounds as faras an intramolecular cyclization reaction does not occur.

The equivalent ratio of the halomethyl group of the vinylbenzyl halideto the halomethyl group of the dihalomethyl compound can be selected asfar as gelation is not caused by the dihalomethyl compound. Theequivalent ratio of the vinylbenzyl halide to the dihalomethyl compoundis preferably in the range of 1.0/0 to 0.1/0.9. When the amount of thevinylbenzyl halide is below the above range, curability deteriorates andthe physical properties such as heat resistance of the cured productdeteriorate.

Examples of the reaction solvent include aprotic polar solvents such asdimethylformamide, dimethyl sulfoxide, dimethyl acetamide,N-methylpyrrolidone, dioxane, acetonitrile, tetrahydrofuran, ethyleneglycol dimethyl ether, 1,3-dimethoxypropane, 1,2-dimethoxypropane,tetramethylene sulfone, hexamethyl phosphamide, methyl ethyl ketone,methyl isobutyl ketone, acetone and cyclohexanone, and mixtures thereof.A solvent may be selected from among these according to the types of rawmaterials and reaction conditions so that a reaction system becomesuniform.

Examples of the alkali used in the present invention include alkoxides,hydrides and hydroxides of an alkali metal or alkali earth metal such assodium methoxide, sodium ethoxide, sodium hydride, sodium borohydride,potassium hydride and potassium hydroxide. The alkali may be selectedaccording to whether the reaction system is made hydrous or anhydrous.

The amount of the alkali is preferably 1.1 to 3.0 equivalents based on 1equivalent of the hydrogen atom at the 9-position of the fluorenecompound as a raw material. When the amount is less than 1.1equivalents, the reaction rate becomes very low and the reaction doesnot proceed completely, with the result that the raw materials remainand an undesirable influence is exerted on the physical properties ofthe cured product. When the amount is beyond 3 equivalents in use, alarge amount of a solvent for removing the residual alkali, such aswashing water, must be used, which is not economical.

A phase-transfer catalyst may be used for the reaction in the presentinvention. Examples of this phase-transfer catalyst include onium saltssuch as quaternary ammonium compounds including tetra-n-butylammoniumbromide, tetra-n-butylammonium hydrogen sulfate, benzyltrimethylammoniumchloride and tricaprylmethylammonium chloride, quaternary phosphoniumcompounds including tetra-n-butylphosphonium bromide,benzyltriphenylphosphonium chloride, tetraphenylphosphonium chloride andtetraphenylphosphonium bromide, and tertiary sulfonium compounds such asbenzyltetramethylene sulfonium bromide, and mixtures thereof.

The amount of the phase-transfer catalyst used cannot be completelyspecified because catalytic effect differs according to the type ofcatalyst or the reaction temperature. However, it is generally about0.01 to 0.2 equivalent based on 1 equivalent of the hydrogen atom at the9-position of the fluorene compound as a raw material.

The reaction temperature and reaction time cannot be completelyspecified because they differ according to the types of raw materialcompound and the reaction conditions but may be preferably 30 to 100° C.and 0.5 to 20 hours, respectively. When the reaction temperature ishigher than 100° C., an unpreferred reaction such as thermalpolymerization occurs and when the reaction temperature is lower than30° C., though the reaction proceeds, it takes a long time, which is noteconomical.

Since a highly polymerizable unsaturated halide such as vinylbenzylhalide is used in the present invention, a thermal polymerizationinhibitor may be optionally added to the reaction system. Examplesthereof include t-butylcatechol, 2,4-di-t-butylphenol, 2-t-butylphenol,2-t-butyl-4-nitrophenol, 2,4-dinitrophenol, hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, t-butylhydroquinone,resorcin, pyrogallol, phenothiazine or copper salt. Further, use of asuitable amount of air is effective in inhibiting polymerization.

The amount of the thermal polymerization inhibitor used cannot becompletely specified because its effect differs according to the type ofthermal polymerization inhibitor. However, an inhibitor of several ppmto 2,000 ppm based on the curable vinylbenzyl compound is sufficient.

The curable polyvinyl benzyl compound represented by the above generalformula 1 of the present invention is obtained by the above productionprocess. In the general formula 1, the divalent organic group of R¹ isderived from the carbon chain of the dihalomethyl compound. Also, n maybe duly determined according to the desired degree of polymerization andmechanical strength and R² is determined according to the type offluorene compound.

The curable polyvinyl benzyl compound of the present invention may bemixed with a monomer, oligomer and/or polymer copolymerizable with theabove compound without departing from the gist of the present inventionto prepare a curable resin composition having improved moldability.Specific examples of the monomer, oligomer and polymer include oligomersand polymers having a polymerizable unsaturated group, such as vinylester resins, unsaturated polyester resins, diallyl phthalate resins,maleimide resins and polycyanate resins of polyphenol, monomers andprepolymers such as triallyl isocyanurate and triallyl cyanurate,styrene, vinyltoluene, divinylbenzene, vinylbenzyl ether compounds, andmonofunctional and polyfunctional (meth)acrylic acid derivativecompounds.

The total use amount of the above copolymerizable monomer, oligomerand/or polymer cannot be completely specified because it differsaccording to the types thereof, compatibility with the vinylbenzylcompound and the intended application of the cured product. It is 0 to300 parts by weight, preferably 0 to 200 parts by weight based on 100parts by weight of the curable polyvinyl benzyl compound. It is morepreferably 10 to 100 parts by weight. An addition amount beyond 300parts by weight is undesirable because separation and exudation from thecurable polyvinyl benzyl compound readily occur.

The curable polyvinyl benzyl compound and curable resin composition ofthe present invention can be cured by a known method such as heat, lightor an electron beam. It is also useful to reduce the curing temperatureor promote a curing reaction by using a curing agent. The cured productcan be suitably used in organic insulating materials, etc. for use inelectronic equipment such as communications equipment.

When a curing agent is used, benzoyl peroxide, cumene hydroperoxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3,t-butylcumyl peroxide, methylethyl ketone peroxide, dicumyl peroxide or t-butyl perbenzoate forexample, may be used according to the intended application.

The amount of the curing agent used differs according to the type andcontent of an unsaturated group contained in the curable polyvinylbenzyl compound or the curable resin composition, the type of the usedcuring agent, the half-life temperature and required stability, but isgenerally 0 to 10 parts by weight based on 100 parts by weight of thecurable polyvinyl benzyl compound or the curable resin composition.

In addition, a known curing accelerator such as manganese naphthenate,lead naphthenate, zinc naphthenate, cobalt naphthenate, zinc octylate,dimethyl aniline or phenyl morpholine may also be used.

The curing temperature cannot be completely specified because it differsaccording to the type of the polymerizable unsaturated group and thetype and amount of the curing agent used but it is 20 to 250° C.,preferably 50 to 250° C. A curing temperature less than 20° C. isundesirable because curing may be insufficient.

A known curing retardant such as hydroquinone, benzoquinone or coppersalt may be mixed to adjust curing conditions.

In addition, the curable polyvinyl benzyl compound and/or curable resincomposition of the present invention may be optionally mixed with acolorant, filler and reinforcing fiber by a kneader, blender or roll toprepare a molding material or composite material. Silica, alumina,zirconia, titanium dioxide, magnesium hydroxide, aluminum hydroxide orcalcium carbonate may be added as the filler without departing from thegist of the present invention.

The above curable polyvinyl benzyl compound or curable resin compositionis molded in a desired shape to obtain a high-frequency substrate of thepresent invention. The high-frequency substrate of the present inventionis suitable for use at a high frequency range of 100 MHz or higher, inparticular, 1 GHz or higher. The dielectric dissipation factor can bemaintained at about 0.002 to 0.01 at this high frequency range.

The present invention further provides a prepreg which is obtained byimpregnating the above curable resin composition with a fiber material.

A known fiber material such as glass fiber, carbon fiber, aromaticpolyamide fiber, silicon carbide fiber or alumina fiber may be used asthe fiber material used in the preparation of the prepreg of the presentinvention. It is preferably glass cloth formed from a glass fiber havinglow dielectric properties (a low dielectric constant and a lowdielectric dissipation factor). A fiber material content of 30 to 70 wt% based on the prepreg is preferable from the viewpoints of strength andmoldability.

In the present invention, to impregnate the curable resin compositionwith the fiber material, either a known solvent method or a solvent-freemethod may be used. As for the solvent to be used in the solvent method,a solvent having a relatively low boiling point such as a ketone-basedsolvent exemplified by acetone, methyl ethyl ketone and methyl isobutylketone, or an aromatic hydrocarbon-based solvent exemplified by benzeneand toluene may be used in order to reduce the amount of the residualsolvent contained in the prepreg as much as possible and avoid areduction in heat resistance, cracking or the formation of voids.

A prepreg can be obtained by drying and heating the fiber material intowhich the curable resin composition is impregnated by the above methodat 80 to 130° C. for 10 to 180 minutes as required.

A high-frequency substrate can be obtained by heating and pressurizingthe obtained single prepreg or a laminate of the prepregs. That is, thehigh-frequency substrate can be obtained by molding a single prepreghaving a predetermined thickness or a laminate of prepregs having apredetermined total thickness by applying heat and pressure inaccordance with a known method such as thermal pressing. The moldingconditions include a temperature of 80 to 250° C., preferably 100 to200° C., a pressure of 5 to 100 kg/cm², and a time of 0.5 to 10 hours,for example. It is also effective to increase the temperature stepwiseas required.

The present invention also provides a metal-lined high-frequencysubstrate which is obtained by placing a metal foil on the above prepregalone or the laminate of the prepregs and applying heat and pressure.That is, a metal-lined high-frequency substrate can be obtained byplacing a metal foil on both sides of a single prepreg having apredetermined thickness or a laminate of prepregs having a predeterminedtotal thickness and molding it by applying heat and pressure asdescribed above.

The metal foil used in the present invention can be copper, gold, silveror aluminum foil but is preferably a copper foil. An electrolytic foilor rolled foil may be optionally used.

Further, by applying the above curable resin composition or a solutionthereof to a metal foil such as the above copper foil using a doctorblade coating or the like, and drying and heating it at 80 to 130° C.for 10 to 180 minutes, it is also possible to obtain a metal foil havinga resin wherein both the foil and the resin composition (or a solutionthereof) are integrated. This metal foil may then be used as ahigh-frequency substrate. A multi-layer laminate substrate may beproduced by placing this metal foil having a resin on a core materialand molding it by applying heat and pressure.

According to the present invention, there is provided a multi-layerlaminate substrate obtained by applying the above curable resincomposition onto a conductive layer, polymerizing and curing thecomposition and further forming a conductive layer on the cured product.

This multi-layer laminate substrate can be manufactured by a so-calledbuild-up process in which an 18 μm-thick copper foil is used as aconductive layer, the curable resin composition is applied onto theconductive layer with a thickness of 20 to 200 μm, preferably 50 to 100μm as an insulating layer, and thermally cured, and further a conductivelayer is formed on the cured product.

The prepreg and the metal foil having a resin obtained by using theabove curable resin composition have been described above. The curablevinylbenzyl compound of the present invention may be used in place ofthe curable resin composition.

A second curable vinylbenzyl compound of the present invention is acompound represented by the following general formula 3:

(wherein, R³, R⁴, and R each represent a group selected from the groupconsisting of a vinylbenzyl group, a hydrogen atom, an alkyl group,alkoxy group, and thioalkoxy group each having 1 to 5 carbon atoms,which may be the same or different, and an aryl group; at least one ofR³, R⁴, and R⁵ is a vinylbenzyl group; and R⁶ represents at least onegroup selected from the group consisting of a hydrogen atom, a halogenatom, an alkyl group, alkoxy group, and thioalkoxy group each having 1to 5 carbon atoms, which may be the same or different, a thioaryloxygroup, and an aryl group).

The second curable vinylbenzyl compound of the present invention can beobtained by reacting at least one indene compound represented by thefollowing general formula 5 and a vinylbenzyl halide in the presence ofan alkali:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

A third curable vinylbenzyl compound of the present invention is acompound represented by the following general formula 4:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group; R⁷represents a divalent organic group having 2 to 20 carbon atoms; R⁸represents a group selected from the group consisting of a vinylbenzylgroup, a hydrogen atom, an alkyl group, alkoxy group, and thioalkoxygroup each having 1 to 5 carbon atoms, which may be the same ordifferent, and an aryl group; at least one R⁸ is a vinylbenzyl group;and a, b, and c each represent an integer of 0 to 20).

The third curable vinylbenzyl compound of the present invention can beobtained by reacting at least one indene compound represented by theabove general formula 5, a vinylbenzyl halide, and a dihalomethylcompound having 2 to 20 carbon atoms in the presence of an alkali. Thedihalomethyl compound used in the present invention is a compound having2 dihalomethyl groups, that is, 2-CH₂X (where X represents a halogenatom) groups in a molecule.

Further, a fourth curable vinylbenzyl compound of the present inventionmay be a curable vinylbenzyl compound obtained by reacting at least oneindene compound represented by the above general formula 5, a fluorenecompound, a vinylbenzyl halide, and a dihalomethyl compound having 2 to20 carbon atoms in the presence of an alkali.

A vinylbenzylation reaction of the above-mentioned materials in thepresent invention can be carried out in the presence of an alkali, in anorganic solvent or an aqueous solution, preferably in the presence of atleast one of an aprotic solvent and a phase-transfer catalyst. Thevinylbenzylation reaction is described by L. J. Mathias et al. in J.Polym. Sci., Part B; 36, 2869 (1998) and in J. Polym. Sci., Part A; 35,587 (1997) and by C. J. Kelly et al. in J. Chem. Res. (S), 446 (1997),for example.

Examples of the indene compound used in the present invention include anindene compound whose indene and aromatic ring parts thereof may besubstituted with a halogen atom, an alkyl group, alkoxy group, orthioalkoxy group each having 1 to 5 carbon atoms, or an aryl group asrepresented by the above general formula 5. The indene compound may beused alone or in combination of two or more compounds. The substitutedindene compound may be synthesized easily by halogenating an aromaticpart of indene with bromine or the like and introducing a desired groupinto the halogenated part.

The fluorene compound used in the present invention is preferably acompound represented by the following general formula 6:

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

In a case where the fluorene compound is used, an equivalent ratio ofthe fluorene compound to the indene compound is preferably adjusted to0.9:0.1 to 0.1:0.9 for a reaction. A large equivalent ratio of thefluorene compound tends to provide a linear compound, and a largeequivalent ratio of the indene compound tends to provide a branchedcompound.

Examples of the vinylbenzyl halide used in the present invention includem-vinylbenzyl chloride, p-vinylbenzyl chloride, m-vinylbenzyl bromide,and p-vinylbenzyl bromide. The vinylbenzyl halide may be used alone orin combination of two or more compounds. Of those, m-vinylbenzylchloride and p-vinylbenzyl chloride are preferred.

Examples of the organic compound having 2 to 20 carbon atoms containinga dihalomethyl group include: alkylene dihalides such as1,2-dichloroethane, 1,2-dibromoethane, 1,3-dichloropropane,1,3-dibromopropane, 1,4-dichlorobutane, and 1,4-dibromobutane; anddihalomethyl compounds such as o-xylylene dichloride, o-xylylenedibromide, m-xylylene dichloride, m-xylylene dibromide, p-xylylenedichloride, p-xylylene dibromide, 4,4′-bis(chloromethyl)biphenyl,4,4′-bis(chloromethyl)diphenyl ether, 4,4′-bis(chloromethyl)diphenylsulfide, 2,6-bis(bromomethyl)naphthalene,1,8-bis(bromomethyl)naphthalene, and 1,4-bis(chloromethyl)naphthalene.The organic compound may be used alone or in combination of two or morecompounds as far as an intramolecular cyclization reaction does notoccur.

The equivalent ratio of the halomethyl group of the vinylbenzyl halideto the halomethyl group of the dihalomethyl compound having 2 to 20carbon atoms can be selected as far as gelation is not caused by thedihalomethyl compound. The equivalent ratio of the halomethyl group ofthe vinylbenzyl halide to the halomethyl group of the dihalomethylcompound having 2 to 20 carbon atoms is preferably adjusted to the rangeof 0.9:0.1 to 0.1:0.9 for a reaction. An equivalent ratio of thevinylbenzyl halide of less than 0.1 deteriorates curability, therebydeteriorating physical properties of the cured product such as heatresistance.

Examples of the alkali used in the present invention include alkoxides,hydrides, and hydroxides of an alkali metal or an alkali earth metalsuch as sodium methoxide, sodium ethoxide, sodium hydride, potassiumhydride, sodium hydroxide, and potassium hydroxide. The alkali may beselected according to whether a reaction system is a nonaqueous systemor a hydrous system.

The amount of the alkali used is preferably 1.1 to 3.0 equivalents withrespect to 1 equivalent of the halomethyl group as a raw material. Analkali of less than 1.1 equivalents causes a very low reaction rate andthe reaction does not proceed completely, thereby resulting in remainedraw materials and providing an adverse effect on the physical propertiesof the cured product. An alkali used exceeding 3 equivalents requires alarge amount of washing water or the like for removing the residualalkali, which is not economical.

Examples of the reaction solvent include: dimethylformamide, dimethylsulfoxide, dimethyl acetamide, N-methylpyrrolidone, dioxane,acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether,1,3-dimethoxypropane, 1,2-dimethoxypropane, tetramethylene sulfone,hexamethylphosphamide, methyl ethyl ketone, methyl isobutyl ketone,acetone, cyclohexanone, methylcyclohexane, toluene, and xylylene; andmixtures thereof. A solvent may be selected from those according to thetypes of raw materials and reaction conditions for a homogeneousreaction system. Of those, an aprotic polar solvent is preferred.

A phase-transfer catalyst is preferably used in the present invention.Examples of the phase-transfer catalyst include various onium salts.Examples of the onium salts include: quaternary ammonium compounds suchas tetra-n-butylammonium bromide, tetra-n-butylammonium hydrogensulfate, benzyltrimethylammonium chloride, and tricaprylmethylammoniumchloride; quaternary phosphonium compounds such astetra-n-butylphosphonium bromide, benzyltriphenylphosphonium chloride,tetraphenylphosphonium chloride, and tetraphenylphosphonium bromide;tertiary sulfonium compounds such as benzyltetramethylene sulfoniumbromide; and mixtures thereof.

The amount of the phase-transfer catalyst used cannot be necessarilyspecified because catalytic effect differs according to the type ofcatalyst or the reaction temperature. However, an amount of generallyabout 0.01 to 0.5 equivalent with respect to 1 equivalent of thehalomethyl group of the raw material is sufficient.

The reaction temperature and the reaction time cannot be necessarilyspecified because they differ according to the type of raw materialcompound and the reaction conditions but may be preferably 30 to 100° C.and 0.5 to 20 hours, respectively. A reaction temperature exceeding 100°C. may cause an undesirable reaction such as thermal polymerization.Further, a reaction temperature of less than 30° C. requires a longperiod of time for a reaction, though the reaction proceeds, which isnot economical.

The vinylbenzyl halide, which is a highly polymerizable unsaturatedhalide, is used in the present invention, and thus, a thermalpolymerization inhibitor may be optionally added to the reaction system.Examples thereof include t-butylcatechol, 2,4-di-t-butylphenol,2-t-butylphenol, 2-t-butyl-4-nitrophenol, 2,4-dinitrophenol,hydroquinone, methylhydroquinone, hydroquinone monomethyl ether,t-butylhydroquinone, resorcin, pyrogallol, phenothiazine, and a coppersalt. The amount of the thermal polymerization inhibitor used cannot benecessarily specified because its effect differs according to the typeof thermal polymerization inhibitor. However, an amount of the thermalpolymerization inhibitor of several ppm to 2,000 ppm with respect to thecurable vinylbenzyl compound is sufficient.

A curable resin composition of the present invention is prepared bymixing a curable vinylbenzyl compound with a compound copolymerizablewith the curable vinylbenzyl compound for improved moldability and forother purposes.

The copolymerizable compound includes a polymer, an oligomer, and amonomer. Specific examples thereof include: polymers such as a vinylester resin, an unsaturated polyester resin, a diallyl phthalate resin,a maleimide resin, and a polycyanate resin of polyphenol; oligomershaving a polymerizable unsaturated group such as a vinylbenzyl etherresin; monomers and prepolymers such as triallyl isocyanurate andtriallyl cyanurate; and vinylbenzyl compounds of fluorene. Furtherexamples thereof include: monomers such as styrene, vinyl toluene,divinylbenzene, and a vinylbenzyl ether compound; and various knownmonofunctional and polyfunctional (meth)acrylic acid derivativecompounds.

The amount of the copolymerizable compound cannot be necessarilyspecified because it differs according to the type of copolymerizablecompound, compatibility with the curable vinylbenzyl compound, theintended application of the cured product, and the like. However, anamount of the copolymerizable compound is 0 to 300 parts by weight,preferably 0 to 200 parts by weight with respect to 100 parts by weightof the curable vinylbenzyl compound. An amount of the copolymerizablecompound added exceeding 300 parts by weight is undesirable becauseseparation and exudation from the curable vinylbenzyl compound and thelike easily occur.

The curable resin of the present invention is obtained by curing acurable vinylbenzyl compound itself or the curable resin composition.

The curable resin can be cured through a known process such as curingwith heat, light, or an electron beam. It is also useful to promote acuring reaction by using a curing agent.

Examples of the curing agent used according to the intended applicationinclude benzoyl peroxide, cumene hydroperoxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, t-butylcumyl peroxide,methyl ethyl ketone peroxide, dicumyl peroxide, and t-butyl perbenzoate.

The amount of the curing agent used differs according to the type andconcentration of unsaturated group in the curable vinylbenzyl compoundor curable resin composition, the type, half-life temperature, andrequired stability of curing agent used, and the like. However, theamount of the curing agent is generally 0 to 10 parts by weight withrespect to 100 parts by weight of the curable vinylbenzyl compound orcurable resin composition.

In addition, examples of a known curing accelerator that may be usedinclude manganese naphthenate, lead naphthenate, zinc naphthenate,cobalt naphthenate, zinc octylate, dimethyl aniline, and phenylmorpholine.

The curing temperature cannot be necessarily specified because itdiffers according to the type of polymerizable unsaturated group and thetype, amount, and the like of curing agent used. However, the curingtemperature is 20 to 250° C., preferably 50 to 250° C. A curingtemperature of less than 20° C. is undesirable because curing may beinsufficient.

A known curing retardant such as hydroquinone, benzoquinone, or a coppersalt may be mixed to adjust curing conditions.

In addition, at least one of the curable vinylbenzyl compound andcurable resin composition of the present invention may be optionallymixed with a colorant, a filler, or a reinforcing fiber using a kneader,a blender, or a roll to prepare a molding material or a compositematerial. A filler such as silica, alumina, zirconia, titanium dioxide,magnesium hydroxide, aluminum hydroxide, or calcium carbonate may beadded within an amount not impairing the effect of the presentinvention.

The above curable vinylbenzyl compound or curable resin composition ofthe present invention can be molded into a desired shape to produce ahigh-frequency substrate. The high-frequency substrate of the presentinvention is suitable for use at a high frequency range of 100 MHz orhigher, particularly 1 GHz or higher. A dielectric dissipation factorcan be maintained at about 0.002 to 0.01 in the high frequency range.

Further, a prepreg can be obtained by impregnating a fiber material withthe above curable vinylbenzyl compound or curable resin composition.

Examples of a known fiber material which can be used in production ofsuch a prepreg include a glass fiber, a carbon fiber, an aromaticpolyamide fiber, a silicon carbide fiber, and an alumina fiber. A glasscloth formed of a glass fiber having low dielectric properties (a lowdielectric constant and a low dielectric dissipation factor) ispreferably used. A fiber material content is preferably 30 to 70 wt %with respect to the prepreg from the viewpoints of strength,moldability, and the like.

A known solvent process or a solvent-free process may be used toimpregnate the fiber material with the curable vinylbenzyl compound orcurable resin composition. The solvent used in the solvent process is asolvent having a relatively low boiling point for minimizing the amountof the residual solvent in the prepreg and avoiding reduction in heatresistance and formation of cracking or voids. Examples of the solventused in the solvent process include: a ketone-based solvent such asacetone, methyl ethyl ketone, or methyl isobutyl ketone; and an aromatichydrocarbon-based solvent such as benzene or toluene.

A prepreg can be obtained by drying and heating the fiber materialimpregnated with the curable vinylbenzyl compound or curable resincomposition through the above process at 80 to 130° C. for 10 to 180minutes as required.

A high-frequency substrate can be obtained by heating and pressurizingthe obtained single prepreg or a prepreg laminate. That is, ahigh-frequency substrate can be obtained by: molding a single prepreghaving a predetermined thickness or a prepreg laminate having apredetermined total thickness; and molding under heat and pressurethrough a known process such as thermal pressing. The molding conditionsinclude: a temperature of 80 to 250° C., preferably 100 to 200° C.; apressure of 5 to 100 kg/cm²; and a time of 0.5 to 10 hours. It is alsoeffective to increase the temperature stepwise as required.

Further, a metal-lined high-frequency substrate can be obtained by:placing a metal foil onto the above prepreg alone or the prepreglaminate; and heating and pressurizing the whole. A metal-linedhigh-frequency substrate can be obtained by: placing a metal foil oneach side of a single prepreg having a predetermined thickness or aprepreg laminate having a predetermined total thickness; and molding thewhole under heat and pressure as described above.

Examples of the metal foil used in the present invention include copper,gold, silver, and aluminum foil, but the metal foil is preferably acopper foil. An electrolytic foil or a rolled foil may be optionallyused.

Further, a metal foil having a resin in which both a metal foil such asthe above copper foil and a resin composition are integrated can beobtained by: applying the above curable vinylbenzyl compound or curableresin composition or a solution thereof to the foil through a doctorblade coating or the like; and drying and heating the whole at 80 to130° C. for 10 to 180 minutes. The metal foil having a resin may be usedas a high-frequency substrate. A multi-layer laminate substrate may beproduced by placing the metal foil having a resin on a core material andmolding the whole under heat and pressure.

Further, a multi-layer laminate substrate can be produced by: applyingthe above curable vinylbenzyl compound or curable resin composition ontoa conductive layer; polymerizing and curing the composition; andproviding an additional conductive layer on the cured product.

Such a multi-layer laminate substrate can be produced through aso-called build-up process involving: using an 18 μm-thick copper foilas a conductive layer; applying the curable vinylbenzyl compound orcurable resin composition onto the conductive layer with a thickness of20 to 200 μm, preferably 50 to 100 μm as an insulating layer; thermallycuring the compound or the composition; and forming an additionalconductive layer on the cured product.

Hereinafter, the high-frequency substrate of the present invention willbe described in detail.

The high-frequency substrate of the present invention is obtained bypolymerizing and curing a polymerizable composition, and thepolymerizable composition according to the present invention has thefollowing 5 modes:

(1) a composition containing a fluorene compound having at least onepolymerizable unsaturated group in a molecule;

(2) a composition containing an indene compound having at least onepolymerizable unsaturated group in a molecule;

(3) a composition containing a mixture of a fluorene compound having atleast one polymerizable unsaturated group in a molecule and an indenecompound having at least one polymerizable unsaturated group in amolecule;

(4) a composition prepared by mixing a fluorene compound having at leastone polymerizable unsaturated group in a molecule and a compoundcopolymerizable with the fluorene compound; and

(5) a composition prepared by mixing an indene compound having at leastone polymerizable unsaturated group in a molecule and a compoundcopolymerizable with the indene compound.

First, the mode (1) will be described.

The fluorene compound having at least one polymerizable unsaturatedgroup in a molecule is not particularly limited, but is preferably acompound having at least one of an allyl group and a propargyl group asa polymerizable unsaturated group, or a compound having at least onepolymerizable unsaturated group and a vinylbenzyl group.

To be specific, the polymerizable composition of the above mode (1) ispreferably a compound obtained by reacting in the presence of an alkali:at least one compound represented by the following general formula 6 asa fluorene compound; a halogen compound having at least onepolymerizable unsaturated group selected from the group consisting of avinylbenzyl halide, an allyl halide, and a propargyl halide; and adihalomethyl compound having 2 to 20 carbon atoms. Such a compoundpresumably has the halogen compound and dihalomethyl compound bonded toa ninth position of a fluorene skeleton.

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

Examples of the halogen compound having the polymerizable unsaturatedgroup include m-vinylbenzyl chloride, p-vinylbenzyl chloride,m-vinylbenzyl bromide, p-vinylbenzyl bromide, allyl chloride, allylbromide, propargyl chloride, and propargyl bromide. The halogen compoundmay be used alone or in combination of two or more compounds.

The dihalomethyl compound having 2 to 20 carbon atoms is a compoundhaving 2-CH₂X (where X is a halogen atom) groups in a molecule. Examplesof the dihalomethyl compound include: alkylene dihalides such as1,2-dichloroethane, 1,2-dibromoethane, 1,3-dichloropropane,1,3-dibromopropane, 1,4-dichlorobutane, and 1,4-dibromobutane; anddihalomethyl compounds such as o-xylylene dichloride, o-xylylenedibromide, m-xylylene dichloride, m-xylylene dibromide, p-xylylenedichloride, p-xylylene dibromide, 4,4′-bis(chloromethyl)biphenyl,4,4′-bis(chloromethyl)diphenyl ether, 4,4′-bis(chloromethyl)diphenylsulfide, 2,6-bis(bromomethyl)naphthalene,1,8-bis(bromomethyl)naphthalene, and 1,4-bis(chloromethyl)naphthalene.The dihalomethyl compound may be used alone or in combination of two ormore compounds as far as an intramolecular cyclization reaction does notoccur.

The equivalent ratio of the halomethyl group of the halogen compoundhaving a polymerizable unsaturated group to the halomethyl group of thedihalomethyl compound having 2 to 20 carbon atoms can be selected as faras gelation is not caused by the dihalomethyl compound, but ispreferably 0.9/0.1 to 0.1/0.9. An equivalent ratio of the halogencompound having a polymerizable unsaturated group of less than the lowerlimit deteriorates curability, thereby deteriorating physical propertiesof the cured product such as heat resistance.

Examples of the reaction solvent include: dimethylformamide, dimethylsulfoxide, dimethyl acetamide, N-methylpyrrolidone, dioxane,acetonitrile, tetrahydrofuran, ethylene glycol dimethyl ether,1,3-dimethoxypropane, 1,2-dimethoxypropane, tetramethylene sulfone,hexamethylphosphamide, methyl ethyl ketone, methyl isobutyl ketone,acetone, cyclohexanone, methylcyclohexane, toluene, and xylylene; andmixtures thereof. A solvent may be selected from those according to thetypes of raw materials and the reaction conditions for a homogeneousreaction system.

Examples of the alkali used in the present invention include alkoxides,hydrides, and hydroxides of an alkali metal or an alkali earth metalsuch as sodium methoxide, sodium ethoxide, sodium hydride, potassiumhydride, sodium hydroxide, and potassium hydroxide. The alkali may beselected according to whether a reaction system is a nonaqueous systemor a hydrous system.

The amount of the alkali used is preferably 1.1 to 3.0 equivalents withrespect to 1 equivalent of the halomethyl group as a raw material. Analkali of less than 1.1 equivalents causes a very low reaction rate andthe reaction does not proceed completely, thereby resulting in remainedraw materials and providing an adverse effect on the physical propertiesof the cured product. An alkali used exceeding 3 equivalents requires alarge amount of washing water or the like for removing the residualalkali, which is not economical.

A phase-transfer catalyst may be used for a reaction carried out in thepresence of an alkali. Examples of the phase-transfer catalyst includevarious onium salts. Examples of the onium salts include: quaternaryammonium compounds such as tetra-n-butylammonium bromide,tetra-n-butylammonium hydrogen sulfate, benzyltrimethylammoniumchloride, and tricaprylmethylammonium chloride; quaternary phosphoniumcompounds such as tetra-n-butylphosphonium bromide,benzyltriphenylphosphonium chloride, tetraphenylphosphonium chloride,and tetraphenylphosphonium bromide; tertiary sulfonium compounds such asbenzyltetramethylene sulfonium bromide; and mixtures thereof.

The amount of the phase-transfer catalyst used cannot be necessarilyspecified because a catalytic effect differs according to the type ofcatalyst or the reaction temperature. However, an amount of generallyabout 0.01 to 0.5 equivalent with respect to 1 equivalent of thehalomethyl group of the raw material is sufficient.

The reaction temperature and the reaction time cannot be necessarilyspecified because they differ according to the type of raw materialcompound and the reaction conditions but may be preferably 30 to 100° C.and 0.5 to 20 hours, respectively. A reaction temperature exceeding 100°C. may cause an undesirable reaction such as thermal polymerization.Further, a reaction temperature of less than 30° C. requires a longperiod of time for a reaction, though the reaction proceeds, which isnot economical.

A polymerization inhibitor may be optionally added to the reactionsystem. Examples thereof include t-butylcatechol, 2,4-di-t-butylphenol,2-t-butylphenol, 2-t-butyl-4-nitrophenol, 2,4-dinitrophenol,hydroquinone, methylhydroquinone, hydroquinone monomethyl ether,t-butylhydroquinone, resorcin, pyrogallol, phenothiazine, and a coppersalt. The amount of the polymerization inhibitor used cannot benecessarily specified because its effect differs according to the typeof polymerization inhibitor. However, an amount of the polymerizationinhibitor of several ppm to 2,000 ppm with respect to the curablevinylbenzyl compound is sufficient.

Next, the mode (2) will be described.

The indene compound having at least one polymerizable unsaturated groupin a molecule is not particularly limited, but is preferably a compoundhaving at least one of a vinylbenzyl group, an allyl group, and apropargyl group as a polymerizable unsaturated group.

To be specific, the polymerizable composition of the above mode (2) ispreferably a compound obtained by reacting in the presence of an alkali:at least one compound represented by the following general formula 5 asan indene compound; a halogen compound having at least one polymerizableunsaturated group selected from the group consisting of a vinylbenzylhalide, an allyl halide, and a propargyl halide; and a dihalomethylcompound having 2 to 20 carbon atoms. Such a compound presumably has thehalogen compound and dihalomethyl compound bonded to first and thirdpositions of an indene skeleton.

(wherein, R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group).

The halogen compound having the polymerizable unsaturated group, thedihalomethyl compound having 2 to 20 carbon atoms, the equivalent ratioof both the compounds, the reaction solvent, the alkali, thephase-transfer catalyst, the reactions conditions, and the like are thesame as those in the above mode (1).

Next, the mode (3) will be described.

In the mode (3), the fluorene compound having at least one polymerizableunsaturated group in a molecule and the indene compound having at leastone polymerizable unsaturated group in a molecule are the same as thosein the above modes (1) and (2). In this case, a mixing ratio of thefluorene compound to the indene compound is 0.1/0.9 to 0.9/0.1 (inweight ratio).

Next, the mode (4) will be described.

In the mode (4), the fluorene compound having at least one polymerizableunsaturated group in a molecule is the same as that in the above mode(1).

The compound copolymerizable with the fluorene compound includes apolymer, an oligomer, and a monomer. Specific examples thereof include:polymers such as a vinyl ester resin, an unsaturated polyester resin, adiallyl phthalate resin, a maleimide resin, and a polycyanate resin ofpolyphenol; oligomers having a polymerizable unsaturated group such as avinylbenzyl ether resin; monomers and prepolymers such as triallylisocyanurate and triallyl cyanurate; and vinylbenzyl compounds offluorene. Further examples thereof include: monomers such as styrene,vinyl toluene, divinylbenzene, and a vinylbenzyl ether compound; andvarious known monofunctional and polyfunctional (meth)acrylic acidderivative compounds.

The amount of the copolymerizable compound cannot be necessarilyspecified because it differs according to the type of copolymerizablecompound, compatibility, the intended application of the cured product,and the like. However, an amount of the copolymerizable compound is 0 to300 parts by weight, preferably 0 to 100 parts by weight with respect to100 parts by weight of the fluorene compound. An amount of thecopolymerizable compound used exceeding 300 parts by weight isundesirable because deterioration of dielectric properties, separationand exudation from the compound, and the like easily occur.

Next, the mode (5) will be described.

In the mode (5), the indene compound having at least one polymerizableunsaturated group in a molecule is the same as that in the above mode(2). The compound copolymerizable with the indene compound and theamount thereof used are the same as those in the above mode (4).

The dielectric constants or flame retardance of the polymerizablecompositions of the 5 modes may be controlled by mixing a filler or aflame retardant using a kneader, a blender, a roll, or the like.Examples of the filler include silica, alumina, zirconia, titaniumdioxide, magnesium hydroxide, aluminum hydroxide, calcium carbonate, andvarious dielectric ceramics. Examples of the flame retardant includecommercially available halogen-based, phosphorus-based, andnitrogen-based flame retardants.

The polymerizable composition can be polymerized and cured through aknown process such as polymerizing and curing with heat, light, or anelectron beam. It is also useful to promote a curing reaction by using acuring agent.

The curing temperature cannot be necessarily specified because itdiffers according to the type of polymerizable unsaturated group and thetype, amount, and the like of curing agent used. However, the curingtemperature is 20 to 250° C., preferably 50 to 250° C. A curingtemperature of less than 20° C. is undesirable because curing may beinsufficient.

Examples of the curing agent used according to the intended applicationinclude benzoyl peroxide, cumene hydroperoxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, t-butylcumyl peroxide,methyl ethyl ketone peroxide, dicumyl peroxide, and t-butyl perbenzoate.

The amount of the curing agent used differs according to the type andconcentration of unsaturated group in the polymerizable composition, thetype, half-life temperature, and required stability of curing agentused, and the like. However, the amount of the curing agent is generally0 to 10 parts by weight with respect to the composition.

In addition, examples of a known curing accelerator that may be usedinclude manganese naphthenate, lead naphthenate, zinc naphthenate,cobalt naphthenate, zinc octylate, dimethyl aniline, and phenylmorpholine.

A known curing retardant such as hydroquinone, benzoquinone, or a coppersalt may be mixed to adjust curing conditions.

The high-frequency substrate of the present invention obtained bypolymerizing and curing the polymerizable composition for molding into adesired shape is suitable for use at a high frequency range of 100 MHzor higher, particularly 1 GHz or higher. A dielectric dissipation factorcan be maintained at about 0.002 to 0.01 in the high frequency range.

Further, the prepreg of the present invention can be obtained byimpregnating a fiber material with the above polymerizable composition.

Examples of a known fiber material which can be used in production ofthe prepreg of the present invention include a glass fiber, a carbonfiber, an aromatic polyamide fiber, a silicon carbide fiber, and analumina fiber. A glass cloth formed of a glass fiber having lowdielectric properties (a low dielectric constant and a low dielectricdissipation factor) is preferably used. A fiber material content ispreferably 30 to 70 wt % with respect to the prepreg from the viewpointsof strength, moldability, and the like.

A known solvent process or a solvent-free process may be used toimpregnate the fiber material with the polymerizable composition. Thesolvent used in the solvent process is a solvent having a relatively lowboiling point for minimizing the amount of the residual solvent in theprepreg and avoiding reduction in heat resistance and formation ofcracking or voids. Examples of the solvent used in the solvent processinclude: a ketone-based solvent such as acetone, methyl ethyl ketone, ormethyl isobutyl ketone; and an aromatic hydrocarbon-based solvent suchas benzene or toluene.

A prepreg can be obtained by drying and heating the fiber materialimpregnated with the polymerizable composition through the above processat 80 to 130° C. for 10 to 180 minutes as required.

A high-frequency substrate can be obtained by heating and pressurizingthe obtained single prepreg or a prepreg laminate. That is, ahigh-frequency substrate can be obtained by: molding a single prepreghaving a predetermined thickness or a prepreg laminate having apredetermined total thickness; and molding under heat and pressurethrough a known process such as thermal pressing. The molding conditionsinclude: a temperature of 80 to 250° C., preferably 100 to 200° C.; apressure of 5 to 100 kg/cm²; and a time of 0.5 to 10 hours. It is alsoeffective to increase the temperature stepwise as required.

Further, a metal-lined high-frequency substrate of the present inventionis obtained by: placing a metal foil onto the above prepreg alone or theprepreg laminate; and heating and pressurizing the whole. A metal-linedhigh-frequency substrate can be obtained by: placing a metal foil oneach side of a single prepreg having a predetermined thickness or aprepreg laminate having a predetermined total thickness; and molding thewhole under heat and pressure as described above.

Examples of the metal foil used in the present invention include copper,gold, silver, and aluminum foil, but the metal foil is preferably acopper foil. An electrolytic foil or a rolled foil may be optionallyused.

Further, a metal foil having a resin in which both a metal foil such asthe above copper foil and the polymerizable composition are integratedcan be obtained by: applying the polymerizable composition or a solutionthereof to the foil through a doctor blade coating or the like; anddrying and heating the whole at 80 to 130° C. for 10 to 180 minutes. Themetal foil having a resin may be used as a high-frequency substrate. Amulti-layer laminate substrate may be produced by placing the metal foilhaving a resin on a core material and molding the whole under heat andpressure.

Further, a multi-layer laminate substrate is obtained by: applying theabove polymerizable composition onto a conductive layer; polymerizingand curing the composition; and providing an additional conductive layeron the cured product.

Such a multi-layer laminate substrate can be produced through aso-called build-up process involving: using an 18 μm-thick copper foilas a conductive layer; applying the polymerizable composition onto theconductive layer with a thickness of 20 to 200 μm, preferably 50 to 100μm as an insulating layer; thermally curing the compound or thecomposition; and forming an additional conductive layer on the curedproduct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an ¹H-NMR spectrum of a compound 1 obtained in Example 1;

FIG. 2 shows an IR spectrum of the compound 1 obtained in Example 1;

FIG. 3 shows the ¹H-NMR spectrum of a compound 2 obtained in Example 2;

FIG. 4 shows the IR spectrum of the compound 2 obtained in Example 2;and

FIG. 5 shows the ¹H-NMR spectrum of a compound 5 obtained in Example 4.

FIG. 6 shows the ¹H-NMR spectrum of a compound 6 obtained in Example 9;

FIG. 7 shows the IR spectrum of a compound 6 obtained in Example 9.

FIG. 8 shows the ¹H-NMR spectrum of a compound 7 obtained in Example 10;

FIG. 9 shows the IR spectrum of a compound 7 obtained in Example 10.

FIG. 10 shows the ¹H-NMR spectrum of a compound 10 obtained in Example13;

FIG. 11 shows the IR spectrum of a compound 10 obtained in Example 13.

FIG. 12 shows the ¹H-NMR spectrum of a compound 13 obtained in Example14;

FIG. 13 shows the ¹H-NMR spectrum of a compound 14 obtained in Example15.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described based on examplesand comparative examples. However, the present invention is not limitedto those examples. The term “parts” in the examples means “parts byweight” unless otherwise stated. Measurement methods carried out inExamples 1 to 4 and Comparative Examples 1 and 2 are shown below.

(1) Weight reduction start temperature: measured under a nitrogen flowat a temperature increase rate of 10° C./min using TG/DTA6200 availablefrom SII Co., Ltd.

(2) Dielectric properties: measured using the 4285A and 4285B LCR metersavailable from Yokogawa Hewlett Packard Co., Ltd. in accordance with anequilibrium bridge method (1 MHz).

(3) ¹H-nuclear magnetic resonance spectrum (¹H-NMR): measured usingtetramethylsilane as an internal standard material and the JNM-LA300available from JEOL Ltd.

(4) IR spectrum: measured using the Fourier Transform InfraredSpectrophotometer, JIR-RFX3002 FT-IR SPECTROPHOTOMETER available fromJEOL Ltd.

(5) Gel permeation chromatography (GPC): The molecular weight (Mw) interms of standard polystyrene was measured at a column temperature of40° C. and an elution rate of 1 ml/min using tetrahydrofuran as aneluate and the Shodex GPC System-21 (column KF-802, KF-803, KF-805)available from Showa Denko K.K.

(6) Water absorption: calculated from dry weight and weight after theabsorption of water by immersing a test specimen measuring 1.5 mm×50mm×50 mm in water at 25° C. for 24 hours.

EXAMPLE 1

49.8 g (0.3 mol) of fluorene, 200 g of methylisobutyl ketone, 2.91 g(9×10⁻³ mol) of tetra-n-butylammonium bromide, 0.73 g of hydroquinoneand 96 g of a 50 wt % aqueous solution of NaOH (NaOH purity of 95%, 1.14mol) were charged into a 1-liter four-necked flask equipped with athermoregulator, stirrer, cooling condenser and dropping funnel andheated at 62° C. under agitation to prepare a uniform solution. 117 g ofvinylbenzyl chloride CMS-AM (m-/p-isomers: 50/50 wt % mixture) availablefrom Seimi Chemical Co., Ltd. (purity of 91%, 0.7 mol) was addeddropwise to this dark blue green solution over 20 minutes and then areaction was carried out at 60 to 61° C. for 7 hours. After 200 ml oftoluene was added to the obtained green reaction product, the obtainedsolution was neutralized with 2N hydrochloric acid and washed withdistilled water three times, toluene was removed under reduced pressure,and the obtained light yellow viscous solid was recrystallized fromfresh toluene to obtain 73.4 g of a gray white solid having a meltingpoint measured by DSC of 142° C. (yield of 61.5%). This is designated ascompound 1.

Compound 1 was identified from its ¹H-NMR spectrum, IR spectrum and GPCmeasurement. FIG. 1 shows the ¹H-NMR spectrum and FIG. 2 shows the IRspectrum. It was found from the GPC measurement results that the producthad an Mw of 400 and it was judged from these measurement results thatthe product was 9,9-bis(vinylbenzyl)fluorene (in the general formula 1,R² is a hydrogen atom and n=0).

The compound 1 was placed in a mold heated at 150° C. and press-cured at150° C. with a pressure of 4.9 MPa to 7.8 MPa (50 to 80 kgf/cm²) for 1hour and at 180° C. with the same pressure for 5 hours to manufacture aresin plate so as to prepare test specimens required for eachmeasurement. The measurement results are shown in Table 1.

EXAMPLE 2

49.8 g (0.3 mol) of fluorene, 220 g of toluene, 2.91 g (9×10⁻³ mol) oftetra-n-butylammonium bromide and 96 g of a 50 wt % aqueous solution ofNaOH (purity of 95%, 1.14 mol) were added to the reactor used in Example1 and heated at 65° C., and 21 g (0.12 mol) of p-xylylene dichloride wasadded, and reacted for 2.5 hours. After it was confirmed from theresults of the ¹H-NMR measurement of a small amount of the reactionproduct that p-xylylene dichloride was consumed, 54 g of CMS-AM (purityof 91%, 0.36 mol) was added dropwise to the reaction system and thereaction was continued at 65° C. for 6.5 hours. After the reactionsolution was cooled to room temperature, 2N hydrochloric acid was addedto neutralize the reaction mixture, and distilled water was added to theorganic layer, which was then washed three times. After the solvent wasdistilled off under reduced pressure, the obtained solid was pulverizedand filtered in methanol to collect solid matter through filtration,which was then dried at 50° C. in a vacuum oven to obtain a curablepolyvinyl benzyl compound at a yield of 90%. The molecular weight Mwmeasured by GPC of the compound was 3,100. The melting point measured byDSC of the compound was 75 to 120° C. This is designated as compound 2.FIG. 3 shows the ¹H-NMR spectrum of this compound and FIG. 4 shows theIR spectrum of the compound. Compound 2 is a compound of the generalformula 1 in which R¹ is a xylylene group, R² is a hydrogen atom andn=about 10 (mixed with a compound in which n=0).

Compound 2 was then poured into the gap between glass plates and curedat 130° C. for 2 hours, at 160° C. for 2 hours and after-cured at 180°C. for 5 hours. Test specimens required for each measurement wereprepared from the obtained resin plate. The measurement results areshown in Table 1.

EXAMPLE 3

A solution containing 60 wt % of Compound 2 synthesized in Example 2 and40 wt % of divinyl benzene (purity of 82%) was prepared, poured into thegap between glass plates and cured at 100° C. for 6 hours, at 160° C.for 4 hours and after-cured at 180° C. for 2 hours. Test specimensrequired for each measurement were prepared from the obtained resinplate. The results are shown in Table 1.

COMPARATIVE EXAMPLE 1

45 g (0.25 equivalent) of dicyclopentadiene skeleton phenolic resin,DPP-3H (special phenolic resin manufactured by Nippon Petrochemical Co.,Ltd.), 38.1 g of vinylbenzyl chloride CMS-AM (m-/p-isomers: 50/50 wt %mixture) (purity of 91%, 0.25 mol), 2.4 g of tetra-n-butylammoniumbromide, 0.038 g of 2,4-dinitrophenol and 200 g of methyl ethyl ketonewere charged into a 1-liter four-necked flask equipped with athermoregulator, stirrer, cooling condenser and dropping funnel anddissolved under agitation, and 40 g of a 50 wt % aqueous solution ofNaOH (NaOH purity of 95%, 0.475 mol) was added dropwise at 75° C. to theobtained solution over 20 minutes and further stirred at 75° C. for 4hours. After the obtained reaction mixture was cooled to roomtemperature, it was neutralized with 2N hydrochloric acid, 100 g oftoluene was added, and the organic layer was then washed three timeswith 300 g of distilled water. After methyl ethyl ketone was removedunder reduced pressure, the reaction product was precipitated in 300 mlof methanol to collect solid matter through filtration, which was thendried at 50° C. in a vacuum oven to obtain a vinylbenzyl ether compoundat a yield of 95%. This is designated as compound 3.

Compound 3 was cured and molded in the same manner as in Example 1 toprepare a resin plate. Test specimens required for each measurement wereprepared from this resin plate. The measurement results are shown inTable 1.

COMPARATIVE EXAMPLE 2

2 parts of 2-ethyl-4-methylimidazole (available from Shikoku Kasei Co.,Ltd.) was mixed with 100 parts of an epoxy resin (Epicoat 828, availablefrom Yuka Shell Epoxy Co., Ltd. (epoxy equivalent 188), to prepare aresin composition. This is designated as compound 4.

Compound 4 was poured into the gap between glass plates and cured at 80°C. for 2 hours and after-cured at 150° C. for 2 hours to manufacture aresin plate. Test specimens required for each measurement were preparedfrom this resin plate. The measurement results are shown in Table 1.

EXAMPLE 4

54.1 g (0.3 mol) of 1-methylfluorene, 200 g of methylisobutyl ketone,2.91 g (9×10⁻³ mol) of tetra-n-butylammonium bromide, 0.73 g ofhydroquinone and 96 g of a 50 wt % aqueous solution of NaOH (NaOH purityof 95%, 1.14 mol) were charged into a 1-liter four-necked flask equippedwith a thermoregulator, stirrer, cooling condenser and dropping funneland heated at 62° C. under agitation to prepare a uniform solution. 117g of vinylbenzyl chloride, CMS-AM (m-/p-isomers: 50/50 wt % mixture)available from Seimi Chemical Co., Ltd. (purity of 91%, 0.7 mol) wasadded dropwise to this dark blue green solution over 20 minutes, whichwas then reacted at 60 to 61° C. for 7 hours. After 200 ml of toluenewas added to the obtained green reaction product, the obtained solutionwas neutralized with 2N hydrochloric acid and washed three times withdistilled water, toluene was removed under reduced pressure, and theobtained light yellow viscous solid was recrystallized from freshtoluene to obtain 75.1 g of a gray white solid having a melting pointmeasured by DSC of 142° C. (yield of 60.8%). This is designated ascompound 5.

Compound 5 was identified from its ¹H-NMR spectrum, IR spectrum and GPCmeasurement. FIG. 5 shows the ¹H-NMR spectrum. It was found from the GPCmeasurement results that the product had an Mw of 410 and it was judgedfrom these measurement results that the product was1-methyl-9,9-bis(vinylbenzyl)fluorene.

Compound 5 was placed in a mold heated at 150° C. and press-cured at150° C. with a pressure of 50 to 80 kgf/cm² for 1 hour and at 180° C.with the same pressure for 5 hours to manufacture a resin plate so as toprepare test specimens required for each measurement. The measurementresults are shown in Table 1. TABLE 1 Mixing ratio ComparativeComparative Example Example Example Example Example Example 1 2 3 1 2 4Compound 1 100 parts Compound 2 100 parts 60 parts Compound 3 100 partsCompound 4 100 parts Compound 5 100 parts Divinylbenzene 40 parts Curedproduct physical properties 5% weight 392° C. 364° C. 378° C. 371° C.399° C. 386° C. reduction temperature Water absorption 0.12% 0.11% 0.12%0.16% 1.4% 0.14% Dielectric 2.65 2.67 2.79 2.82 3.29 2.69 constant (1MHz) Dielectric 0.0013 0.0023 0.0017 0.0070 0.0249 0.0015 dissipationfactor (1 MHz)

It is understood from the results of Table 1 that the curable polyvinylbenzyl compound of the present invention attains better dielectricproperties (lower dielectric constant and lower dielectric dissipationfactor) than the conventional resins of the comparative examples withoutimpairing heat resistance and has stable dielectric properties becauseof its lower water absorption.

EXAMPLE 5

The glass cloth, WEA18K105BZ2 (available from Nitto Boseki Co., Ltd.)was impregnated with a 60% toluene solution of Compound 1 and dried at120° C. for 60 minutes to obtain a prepreg. A 10-ply laminate of theprepregs was prepared and molded through the application of heat andpressure (40 kg/cm²) at 150° C. for 2 hours, at 180° C. for 5 hours andat 200° C. for 5 hours to obtain a laminated plate having a thickness of1.6 mm and a glass fiber content of 60%.

The dielectric properties and solder heat resistance of this laminatedplate were tested by the methods desirable below. As a result, the platehad a dielectric constant of 4.0, a dielectric dissipation factor of0.0035 and a solder heat resistance of 120 seconds or more.

Dielectric properties: The dielectric constant and dielectricdissipation factor at 5 GHz of a prismatic specimen measuring 1.6 mm×1.5mm×75 mm were measured by the vector network analyzer, HP8753E availablefrom Hewlett Packard Co., Ltd. in accordance with a cavity resonatorperturbation method.

Solder heat resistance test: In accordance with JIS C 0054, the specimenwas immersed in a solder bath at 260° C. for 120 seconds to check ifthere was any change in its surface state or shape.

EXAMPLE 6

The procedure of Example 5 was repeated except that the compound 2 wasused in place of compound 1. As a result, the compound had a dielectricconstant of 4.0, a dielectric dissipation factor of 0.0040 and a solderheat resistance of 120 seconds or more.

EXAMPLE 7

The procedure of Example 5 was repeated except that the compound 5 wasused in place of compound 1. As a result, the compound had a dielectricconstant of 4.0, a dielectric dissipation factor of 0.0038 and a solderheat resistance of 120 seconds or more.

EXAMPLE 8

A resin solution prepared by dissolving 100 parts of compound 1 and 120parts of compound 2 in 80 parts of toluene was applied to a 35 μm-thickcopper foil 3EC available from Mitsui Mining & Smelting Co., Ltd. to athickness of 100 μm, dried at 100° C. for 60 minutes and heated at 120°C. for 2 hours to obtain a semi-cured product (two products weremanufactured). These two copper foils having a resin were overlapped insuch a manner that their resins were brought into contact with eachother and molded through the application of heat and pressure at 150° C.for 2 hours and at 180° C. for 6 hours (40 kg/cm²) to obtain a specimen.In accordance with JIS C 6481, this specimen was then used to measurethe copper foil's peel strength, which was 1.2 kgf/cm.

Further, measurement methods carried out in Examples 9 to 15 andReference Examples 1 and 2 are shown below.

Thermogravimetric analysis: measured in a stream of nitrogen at atemperature increase rate of 10° C./minutes using a TGA instrumentavailable from Seiko Instruments Inc.

Dielectric properties: A dielectric constant and a dielectricdissipation factor at 5 GHz of a prism sample of 1.5 mm×1.5 mm×75 mmwere measured using a vector network analyzer HP8753E available fromHewlett-Packard Japan, Ltd. in accordance with a cavity resonatorperturbation method.

¹H-nuclear magnetic resonance spectrum (¹H-NMR): measured usingtetramethylsilane as an internal standard material and JNM-LA300available from JEOL Ltd.

Infrared absorption spectrum (IR): measured using a Fourier transforminfrared spectrophotometer JIR-RFX3002 FT-IR available from JEOL Ltd.

High performance liquid chromatography (HPLC): measured using ShodexR1-51 (columns KF-801, KF-802) available from SHOWA DENKO K.K. at anelution rate of 1 ml/minute using tetrahydrofuran as an elute.

Water absorption: obtained by immersing a sample of 1.5 mm×40 mm×40 mmin water at 25° C. for 24 hours and calculating with a calculationformula [(W2−W1)/W1]×100 from the dry weight (W1) of the sample and theweight of the sample after the absorption of water (W2).

EXAMPLE 9

Inside of a flask equipped with a thermoregulator, a stirrer, a coolingcondenser, a dropping funnel, and a nitrogen inlet was replaced withnitrogen. 34.9 g (0.3 mol) of indene, 200 g of toluene, 8.72 g (0.027mol) of tetra-n-butylammonium bromide, 1.79 g (0.009 mol) ofphenothiazine, and 144.0 g of a 50 wt % aqueous solution of NaOH (NaOH,1.8 mol) were charged into the flask and the mixture was heated to 50°C. under stirring, to thereby prepare a homogeneous solution. 150.8 g ofvinylbenzyl chloride (CMS-AM; purity of 91%; 0.9 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) was addeddropwise to the dark blue green solution over 15 minutes, and a reactionwas then carried out at 50 to 52° C. for 10 hours. The obtained mixturein the flask was neutralized with 2N hydrochloric acid and washed withdistilled water twice, and toluene was distilled off under reducedpressure. The obtained orange viscous liquid was washed with methanoland then dried in vacuum, to thereby obtain a curable vinylbenzylcompound of the present invention (mainly composed of a compound inwhich R³, R⁴, and R⁵ each represent a vinylbenzyl group, and R⁶represents a hydrogen atom in the general formula 3). The obtainedcompound is designated as Compound 6. Compound 6 was identified from its¹H-NMR spectrum, IR spectrum, and HPLC measurement. Compound 6 was ahighly viscous liquid with substantially no fluidity at 23° C. FIG. 6shows the ¹H-NMR spectrum, and FIG. 7 shows the IR spectrum.

Compound 6 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 2 hours, and then at 200° C. for 3 hours to forma resin plate having a thickness of 1.5 mm. Samples required for eachmeasurement were prepared using the resin plate. Table 2 shows theresults of the measurements.

EXAMPLE 10

Inside of a flask equipped with a thermoregulator, a stirrer, a coolingcondenser, a dropping funnel, and a nitrogen inlet was replaced withnitrogen. 46.5 g (0.4 mol) of indene, 200 g of toluene, 7.75 g (0.024mol) of tetra-n-butylammonium bromide, 0.08 g (0.0004 mol) ofphenothiazine, and 128.0 g of a 50 wt % aqueous solution of NaOH (NaOH,1.6 mol) were charged into the flask, and the mixture was heated to 50°C. under stirring, to thereby prepare a homogeneous solution. 134.1 g ofvinylbenzyl chloride (CMS-AM; purity of 91%; 0.8 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) was addeddropwise to the dark blue green solution over 15 minutes, and a reactionwas then carried out at 50 to 52° C. for 10 hours. The obtained mixturein the flask was neutralized with 2N hydrochloric acid and washed withdistilled water twice, and toluene was distilled off under reducedpressure. The obtained orange viscous liquid was washed with methanoland then dried in vacuum, to thereby obtain a curable vinylbenzylcompound of the present invention (consisting of three compounds: acompound in which R³, R⁴, and R⁵ each represent a vinylbenzyl group, andR⁶ represents a hydrogen atom in the general formula 3; a compound inwhich two of R³ to R⁵ represent vinylbenzyl groups and the remainingrepresents a hydrogen atom, and R⁶ represents a hydrogen atom in thegeneral formula 3; and a compound in which one of R³ to R⁵ represents avinylbenzyl group and the remaining represent hydrogen atoms, and R⁶represents a hydrogen atom in the general formula 3). The obtainedcompound is designated as Compound 7. Compound 7 was identified from its¹H-NMR spectrum, IR spectrum, and HPLC measurement. Compound 7 was ahighly viscous liquid of about 5,000 poise at 23° C. FIG. 8 shows the¹H-NMR spectrum, and FIG. 9 shows the IR spectrum.

Compound 7 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 2 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table2 shows the results of the measurements.

EXAMPLE 11

Inside of a flask equipped with a thermoregulator, a stirrer, a coolingcondenser, a dropping funnel, and a nitrogen inlet was replaced withnitrogen. 46.5 g (0.4 mol) of indene, 200 g of toluene, 3.88 g (0.012mol) of tetra-n-butylammonium bromide, 0.04 g (0.0002 mol) ofphenothiazine, and 64.0 g of a 50 wt % aqueous solution of NaOH (NaOH,0.8 mol) were charged into the flask, and the mixture was heated to 50°C. under stirring, to thereby prepare a homogeneous solution. 80.4 g ofvinylbenzyl chloride (CMS-AM; purity of 91%; 0.48 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) was addeddropwise to the dark blue green solution over 15 minutes, and a reactionwas then carried out at 50 to 52° C. for 10 hours. The obtained mixturein the flask was neutralized with 2N hydrochloric acid and washed withdistilled water twice, and toluene was distilled off under reducedpressure. The obtained orange viscous liquid was washed with methanoland then dried in vacuum, to thereby obtain a curable vinylbenzylcompound of the present invention (mainly composed of a compound inwhich one of R³ to R⁵ represents a vinylbenzyl group and the remainingrepresent hydrogen atoms, and R⁶ represents a hydrogen atom in thegeneral formula 3). The obtained compound is designated as Compound 8.Compound 8 was a viscous liquid of about 1,000 poise at 23° C. Compound8 was identified from its ¹H-NMR spectrum, IR spectrum, and HPLCmeasurement in the same manner as in Examples 9 and 10.

Compound 8 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 2 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table2 shows the results of the measurements.

EXAMPLE 12

Inside of a flask equipped with a thermoregulator, a stirrer, a coolingcondenser, a dropping funnel, and a nitrogen inlet was replaced withnitrogen. 46.5 g (0.4 mol) of indene, 200 g of toluene, 3.88 g (0.012mol) of tetra-n-butylammonium bromide, 0.04 g (0.0002 mol) ofphenothiazine, and 64.0 g of a 50 wt % aqueous solution of NaOH (NaOH,0.8 mol) were charged into the flask, and the mixture was heated to 50°C. under stirring, to thereby prepare a homogeneous solution. 67.0 g ofvinylbenzyl chloride (CMS-AM; purity of 91%; 0.40 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) was addeddropwise to the dark blue green solution over 15 minutes, and a reactionwas then carried out at 50 to 52° C. for 10 hours. The obtained mixturein the flask was neutralized with 2N hydrochloric acid and washed withdistilled water twice, and toluene was distilled off under reducedpressure. The obtained orange viscous liquid was washed with methanoland then dried in vacuum, to thereby obtain a curable vinylbenzylcompound of the present invention (mainly composed of a compound inwhich one of R³ to R⁵ represents a vinylbenzyl group and the remainingrepresent hydrogen atoms, and R⁶ represents a hydrogen atom in thegeneral formula 3). The obtained compound is designated as Compound 9.Compound 9 was identified from its ¹H-NMR spectrum, IR spectrum, andHPLC measurement in the same manner as in Examples 9 and 10.

Compound 9 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 2 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table2 shows the results of the measurements.

EXAMPLE 13

166 g (1.43 mol) of indene, 1,000 g of toluene, 22 g (0.069 mol) oftetra-n-butylammonium bromide, 2.50 g (1.43 mol) of p-xylylenedichloride, and 240 g of vinylbenzyl chloride (CMS-AM; purity of 91%;1.43 mol; m-/p-isomers: 50/50 wt % mixture; available from SeimiChemical Co., Ltd.) were charged into a flask equipped with athermoregulator, a stirrer, a cooling condenser, and a dropping funnel,and the mixture was heated to 40° C. under stirring, to thereby preparea homogeneous solution. 344 g of a 50 wt % aqueous solution of NaOH(NaOH, 8.6 mol) was added to the solution, and a reaction was thencarried out at 70° C. for 8 hours. The obtained mixture in the flask wasneutralized with 2N hydrochloric acid and washed with distilled watertwice, and toluene was distilled off under reduced pressure. Theobtained orange viscous liquid was washed with methanol and then driedin vacuum, to thereby obtain a solid compound having a molecular weightMw of 3,000 in which an oligomer compound containing indene connected byxylylene was substituted with a vinylbenzyl group (in which R⁶represents hydrogen, R⁷ represents a xylylene group, R⁸ represents avinylbenzyl group, and a to c represent values providing an Mw of 3,000in the general formula 4). The obtained compound is designated asCompound 10. Compound 10 was identified from its ¹H-NMR spectrum. FIG.10 shows the ¹H-NMR spectrum of Compound 10 obtained in Example 13, andFIG. 9 shows the IR spectrum of Compound 10 obtained in Example 13.

Compound 10 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 2 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table2 shows the results of the measurements.

COMPARATIVE EXAMPLE 3

45 g (0.25 equivalent) of a dicyclopentadiene skeleton phenolic resin(DPP-3H, special phenolic resin, available from Nippon PetrochemicalsCo., Ltd.), 38.1 g of vinylbenzyl chloride (CMS-AM; purity of 91%; 0.25mol; m-/p-isomers: 50/50 wt % mixture; available from Seimi ChemicalCo., Ltd.), 2.4 g of tetra-n-butylammonium bromide, 0.038 g of2,4-dinitrophenol, and 200 g of methyl ethyl ketone were charged into afour-necked flask equipped with a thermoregulator, a stirrer, a coolingcondenser, and a dropping funnel, and the mixture was dissolved understirring. 40 g of a 50 wt % aqueous solution of NaOH (NaOH, 0.48 mol)was added dropwise at 75° C. to the obtained solution over 20 minutes,and a reaction was further carried out at 75° C. for 4 hours. Theobtained mixture in the flask was neutralized with 2N hydrochloric acid,and 100 g of toluene was added. An organic layer was then washed withdistilled water three times. After methyl ethyl ketone was distilled offunder reduced pressure, a reaction product was precipitated in methanolto collect a solid matter through filtration, which was then dried at50° C. in vacuum to obtain a vinylbenzyl ether compound. The obtainedcompound is designated as Compound 11.

Compound 11 was cured and molded into a resin plate in the same manneras in Example 9. Samples required for each measurement were preparedusing the resin plate. Table 2 shows the results of the measurements.

COMPARATIVE EXAMPLE 4

2 parts of 2-ethyl-methylimidazole (available from Shikoku ChemicalsCorporation) was mixed with 100 parts of an epoxy resin (Epicoat 828,epoxy equivalent 188, available from Yuka-Shell Epoxy Co., Ltd.), tothereby prepare a resin composition. The obtained compound is designatedas Compound 12.

Compound 12 was poured between glass plates and cured at 80° C. for 2hours and then at 150° C. for 2 hours, to thereby form a resin plate.Samples required for each measurement were prepared using the resinplate. Table 2 shows the results of the measurements. TABLE 2 Curedproduct Comparative Comparative physical Example Example Example ExampleExample Example Example properties 9 10 11 12 13 3 4 Dielectric 2.662.65 2.70 2.71 2.63 2.85 3.25 constant (5 GHz) Dielectric 0.0018 0.00190.0015 0.0013 0.0041 0.0075 0.0253 dissipation factor (5 GHz) 5% weight410 400 383 377 385 371 399 reduction temperature (° C.) Waterabsorption 0.065 0.050 0.052 0.060 0.070 0.157 1.389 (%)

EXAMPLE 14

116 g (1 mol) of indene, 166 g (1 mol) of fluorene, 1,000 g of toluene,22 g (0.069 mol) of tetra-n-butylammonium bromide, 70 g (0.4 mol) ofp-xylylene dichloride, and 550 g of vinylbenzyl chloride (CMS-AM; purityof 91%; 3.6 mol; m-/p-isomers: 50/50 wt % mixture; available from SeimiChemical Co., Ltd.) were charged into a flask equipped with athermoregulator, a stirrer, a cooling condenser, and a dropping funnel,and the mixture was heated to 40° C. under stirring, to thereby preparea homogeneous solution. 352 g of a 50 wt % aqueous solution of NaOH(NaOH, 8.8 mol) was added to the solution, and a reaction was thencarried out at 70° C. for 8 hours. The obtained mixture in the flask wasneutralized with 2N hydrochloric acid and washed with distilled watertwice, and toluene was distilled off under reduced pressure. Theobtained orange viscous liquid was washed with methanol and then driedin vacuum, to thereby obtain a solid compound having a molecular weightMw of 700 in which an oligomer compound containing fluorene and indeneconnected by xylylene was substituted with a vinylbenzyl group. Theobtained compound is designated as Compound 13. Compound 13 wasidentified from its ¹H-NMR spectrum. FIG. 12 shows the ¹H-NMR spectrumof Compound 13 obtained in Example 14.

Compound 13 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 5 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table3 shows the results of the measurements.

EXAMPLE 15

55 g (0.48 mol) of indene, 237 g (1.43 mol) of fluorene, 1,000 g oftoluene, 22 g (0.069 mol) of tetra-n-butylammonium bromide, 250 g (1.43mol) of p-xylylene dichloride, and 240 g of vinylbenzyl chloride(CMS-AM; purity of 91%; 1.43 mol; m-/p-isomers: 50/50 wt % mixture;available from Seimi Chemical Co., Ltd.) were charged into a flaskequipped with a thermoregulator, a stirrer, a cooling condenser, and adropping funnel, and the mixture was heated to 40° C. under stirring toprepare a homogeneous solution. 344 g of a 50 wt % aqueous solution ofNaOH (NaOH, 8.6 mol) was added to the solution, and a reaction was thencarried out at 70° C. for 8 hours. The obtained mixture in the flask wasneutralized with 2N hydrochloric acid and washed with distilled watertwice, and toluene was distilled off under reduced pressure. Theobtained orange viscous liquid was washed with methanol and then driedin vacuum, to thereby obtain a solid compound having a molecular weightMw of 3,000 in which an oligomer compound containing fluorene and indeneconnected by xylylene was substituted with a vinylbenzyl group. Theobtained compound is designated as Compound 14. Compound 14 wasidentified from its ¹H-NMR spectrum. FIG. 13 shows the ¹H-NMR spectrumof Compound 14 obtained in Example 15.

Compound 14 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 5 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table3 shows the results of the measurements.

REFERENCE EXAMPLE 1

49.8 g (0.3 mol) of fluorene, 220 g of toluene, 2.91 g (9×10⁻³ mol) oftetra-n-butylammonium bromide, and 96 g of a 50 wt % aqueous solution ofNaOH (purity of 95%, 1.14 mol) were charged into a 1-liter four-neckedflask equipped with a thermoregulator, a stirrer, a cooling condenser,and a dropping funnel, and the mixture was heated to 65° C. 21 g (0.12mol) of p-xylylene dichloride was added, and a reaction was carried outfor 2.5 hours. After results of the ¹H-NMR measurement of a small amountof the reaction product confirmed that p-xylylene dichloride wasconsumed, 54 g of CMS-AM (purity of 91%; 0.36 mol) was added dropwise tothe reaction system, and the reaction was continued at 65° C. for 6.5hours. After the reaction liquid was cooled to room temperature, 2Nhydrochloric acid was added to neutralize the reaction mixture. Anorganic layer was washed with distilled water three times. After thesolvent was distilled off under reduced pressure, the obtained solid waspulverized in methanol and filtered to collect a solid matter throughfiltration. The solid matter was then dried at 50° C. in a vacuum oven,to thereby obtain an oligomer compound containing fluorene connected byxylylene. The obtained compound is designated as Compound 15.

Compound 15 was poured between glass plates and was cured at 160° C. for2 hours, at 180° C. for 5 hours, and then at 200° C. for 3 hours, tothereby form a resin plate having a thickness of 1.5 mm. Samplesrequired for each measurement were prepared using the resin plate. Table3 shows the results of the measurements.

REFERENCE EXAMPLE 2

Equal amounts of Compound 10 and Compound 15 were mixed, and the mixturewas poured between glass plates and was cured at 160° C. for 2 hours, at180° C. for 5 hours, and then at 200° C. for 3 hours, to thereby form aresin plate having a thickness of 1.5 mm. Samples required for eachmeasurement were prepared using the resin plate. Table 3 shows theresults of the measurements. TABLE 3 Cured product Reference Referencephysical Example Example Example Example properties 14 15 1 2 Dielectricconstant 2.66 2.63 2.70 2.65 (5 GHz) Dielectric dissipation 0.00310.0038 0.0028 0.0038 factor (5 GHz) 5% weight reduction 405 411 364 376temperature (° C.) Water absorption (%) 0.065 0.070 0.110 0.080

Further, the high-frequency substrate of the present invention will bedescribed, but the present invention is not limited to examples below.The measurement methods carried out in Examples 16 to 19 and ComparativeExamples 5 and 6 are shown below.

Dielectric properties: A dielectric constant and a dielectricdissipation factor at 5 GHz of a prism sample of 1.6 mm×1.5 mm×75 mmwere measured using a vector network analyzer BP8753E available fromHewlett-Packard Japan, Ltd. in accordance with a cavity resonatorperturbation method. ¹H-nuclear magnetic resonance spectrum (¹H-NMR):measured using tetramethylsilane as an internal standard material andJNM-LA300 available from JEOL Ltd.

Gel permeation chromatography (GPC): measured using Shodex GPC System-21(columns KF-802, KF-803, KF-805) available from SHOWA DENKO K.K. at anelution rate of 1 ml/minute using tetrahydrofuran as an elute. The GPCwas adopted for molecular weight determination.

Solder heat resistance test: carried out in accordance with JIS C 0054by immersing a sample in a solder bath at 260° C. for 120 seconds tocheck if there were any changes in a surface state or shape of thesample.

EXAMPLE 16

249 g (1.5 mol) of fluorene, 250 g of toluene, 22 g (0.069 mol) oftetra-n-butylammonium bromide, 76 g (1.0 mol) of allyl chloride, and 335g of vinylbenzyl chloride (CMS-AM; purity of 91%; 2.0 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) werecharged into a flask equipped with a thermoregulator, a stirrer, acooling condenser, a dropping funnel, and an oxygen inlet, and themixture was heated to 40° C. under stirring, to thereby prepare ahomogeneous solution. 240 g of a 50 wt % aqueous solution of NaOH (NaOH,6 mol) was added to the solution, and a reaction was then carried out at60° C. for 8 hours. The obtained mixture in the flask was neutralizedwith 2N hydrochloric acid and washed with distilled water twice, andtoluene was distilled off under reduced pressure. The obtained orangeviscous liquid was dried in vacuum, to thereby obtain a semi-solidcompound containing fluorene substituted with a vinylbenzyl group and anallyl group. The obtained compound is designated as Compound 16.Compound 16 was identified from its ¹H-NMR spectrum.

Next, a glass cloth (WEA18K105BZ2, available from Nitto Boseki Co.,Ltd.) was impregnated with a 60% toluene solution of Compound 16, andthe whole was dried at 120° C. for 60 minutes, to thereby obtain aprepreg. A 10-ply prepreg laminate was prepared and molded under heatand pressure (40 kg/cm²) at 150° C. for 2 hours, at 180° C. for 5 hours,and at 200° C. for 5 hours, to thereby obtain a laminated plate having athickness of 1.6 mm and a glass fiber content of 60%.

EXAMPLE 17

Inside of a flask equipped with a thermoregulator, a stirrer, a coolingcondenser, a dropping funnel, and a nitrogen inlet was replaced withnitrogen. 46.5 g (0.4 mol) of indene, 200 g of toluene, 7.75 g (0.024mol) of tetra-n-butylammonium bromide, 0.08 g (0.0004 mol) ofphenothiazine, and 128.0 g of a 50 wt % aqueous solution of NaOH (NaOH,1.6 mol) were charged into the flask, and the mixture was heated to 50°C. under stirring to prepare a homogeneous solution. 34.1 g ofvinylbenzyl chloride (CMS-AM; purity of 91%; 0.8 mol; m-/p-isomers:50/50 wt % mixture; available from Seimi Chemical Co., Ltd.) was addeddropwise to the dark blue green solution over 15 minutes, and a reactionwas then carried out at 50 to 52° C. for 10 hours. The obtained mixturein the flask was neutralized with 2N hydrochloric acid and washed withdistilled water twice, and toluene was distilled off under reducedpressure. The obtained orange viscous liquid was washed with methanoland then dried in vacuum, to thereby obtain a liquid compound containingindene substituted with a vinylbenzyl group. The obtained compound isdesignated as Compound 17. Compound 17 was identified from its ¹H-NMRspectrum.

Next, a glass cloth (WEA18K105BZ2, available from Nitto Boseki Co.,Ltd.) was impregnated with Compound 17, and the whole was dried at 120°C. for 30 minutes, to thereby obtain a prepreg. A 10-ply prepreglaminate was prepared and molded under heat and pressure (40 kg/cm²) at150° C. for 2 hours and at 180° C. for 6 hours, to thereby to obtain alaminated plate having a thickness of 1.6 mm and a glass fiber contentof 62%.

EXAMPLE 18

55 g (0.48 mol) of indene, 237 g (1.43 mol) of fluorene, 1,000 g oftoluene, 22 g (0.069 mol) of tetra-n-butylammonium bromide, 250 g (1.43mol) of p-xylylene dichloride, and 240 g of vinylbenzyl chloride(CMS-AM; purity of 91%; 1.43 mol; m-/p-isomers: 50/50 wt % mixture;available from Seimi Chemical Co., Ltd.) were charged into a flaskequipped with a thermoregulator, a stirrer, a cooling condenser, and adropping funnel, and the mixture was heated to 40° C. under stirring, tothereby prepare a homogeneous solution. 344 g of a 50 wt % aqueoussolution of NaOH (NaOH, 8.6 mol) was added to the solution, and areaction was then carried out at 70° C. for 8 hours. The obtainedmixture in the flask was neutralized with 2N hydrochloric acid andwashed with distilled water twice, and toluene was distilled off underreduced pressure. The obtained orange viscous liquid was washed withmethanol and then dried in vacuum, to thereby obtain a solid compoundhaving a weight average molecular weight Mw of 3,000 in which anoligomer compound containing fluorene and indene connected by xylylenewas substituted with a vinylbenzyl group. The obtained compound isdesignated as Compound 18. Compound 18 was identified from its ¹H-NMRspectrum.

Next, a glass cloth (WEA18K105BZ2, available from Nitto Boseki Co.,Ltd.) was impregnated with a 60% toluene solution of Compound 18, andthe whole was dried at 120° C. for 60 minutes, to thereby obtain aprepreg. A 10-ply prepreg laminate was prepared and molded under heatand pressure (40 kg/cm²) at 150° C. for 2 hours and at 180° C. for 6hours, to thereby obtain a laminated plate having a thickness of 1.6 mmand a glass fiber content of 60%.

EXAMPLE 19

A glass cloth (WEA18K105BZ2, available from Nitto Boseki Co., Ltd.) wasimpregnated with a 60% toluene solution prepared by adding 10 parts ofphenyl maleimide with respect to 90 parts of Compound 16 obtained inExample 16, and the whole was dried at 120° C. for 60 minutes, tothereby obtain a prepreg. A 10-ply prepreg laminate was prepared andmolded under heat and pressure (40 kg/cm²) at 150° C. for 2 hours, at180° C. for 5 hours, and at 200° C. for 5 hours, to thereby obtain alaminated plate having a thickness of 1.6 mm and a glass fiber contentof 61%.

EXAMPLE 20

A resin solution prepared by dissolving 100 parts of Compound 16obtained in Example 16 and 120 parts of Compound 17 obtained in Example17 in 80 parts of toluene was applied to a 35 μm-thick copper foil (3EC,available from Mitsui Mining & Smelting Co., Ltd.) to a thickness of 100μm. The whole was dried at 100° C. for 60 minutes and heated at 120° C.for 2 hours, to thereby obtain a semi-cured product (two products wereproduced). The two copper foils each having a resin were piled in such amanner that the resins were brought into contact with each other andwere molded under heat and pressure (40 kg/cm²) at 150° C. for 2 hoursand at 180° C. for 6 hours, to thereby obtain a sample. Peel strength ofthe copper foil measured in accordance with JIS C 6481 using the samplewas 1.2 kgf/cm.

COMPARATIVE EXAMPLE 5

45 g (0.25 equivalent) of a dicyclopentadiene skeleton phenolic resin(DPP-3H, special phenolic resin, available from Nippon PetrochemicalCo., Ltd.), 38.1 g of vinylbenzyl chloride (CMS-AM; purity of 91%; 0.25mol; m-/p-isomers: 50/50 wt % mixture; available from Seimi ChemicalCo., Ltd.), 2.4 g of tetra-n-butylammonium bromide, 0.038 g of2,4-dinitrophenol, and 200 g of methyl ethyl ketone were charged into a1-liter four-necked flask equipped with a thermoregulator, a stirrer, acooling condenser, and a dropping funnel and dissolved under stirring.40 g of a 50 wt % aqueous solution of NaOH (NaOH purity of 95%, 0.475mol) was added dropwise at 75° C. to the obtained solution over 20minutes, and the whole was stirred at 75° C. for additional 4 hours.After the obtained reaction mixture was cooled to room temperature, themixture was neutralized with 2N hydrochloric acid, and 100 g of toluenewas added. An organic layer was then washed with 300 g of distilledwater three times. After methyl ethyl ketone was removed under reducedpressure, a reaction product was precipitated in 300 ml of methanol tocollect a solid matter through filtration, which was then dried at 50°C. in a vacuum oven to obtain a vinylbenzyl ether compound at an yieldof 95%. The obtained compound is designated as Compound 19.

Next, a glass cloth (WEA18K105BZ2, available from Nitto Boseki Co.,Ltd.) was impregnated with a resin solution prepared by dissolvingCompound 19 in a 60% toluene solution, and the whole was dried at 120°C. for 90 minutes, to thereby obtain a prepreg. A 10-ply prepreglaminate was prepared and molded under heat and pressure (40 kg/cm²) at150° C. for 2 hours and at 180° C. for 6 hours, to thereby to obtain alaminated plate having a thickness of 1.6 mm and a glass fiber contentof 62%.

COMPARATIVE EXAMPLE 6

A resin solution was prepared by dissolving 90 parts of a bisphenolA-type epoxy resin (Epicoat 1001, available from Japan Epoxy Resins Co.,Ltd.), 10 parts of a novolak-type epoxy resin (DEN 438, available fromDow Chemical Japan Ltd.), 5 parts of dicyandiamide as a curing agent,and 0.3 part of benzyldimethylamine as a curing accelerator in 70 partsof acetone. A glass cloth (WEA18K105BZ2, available from Nitto BosekiCo., Ltd.) was impregnated with the resin solution, and the whole wasdried at 80° C. for 5 minutes and at 160° C. for 5 minutes, to therebyobtain a prepreg. A 10-ply prepreg laminate was prepared and moldedunder heat and pressure (70 kg/cm²) at 160° C. for 1 hour, to thereby toobtain a laminated plate having a thickness of 1.6 mm and a glass fibercontent of 62%.

Table 4 shows the physical properties of the laminated plates obtainedin Examples 16 to 19 and Comparative Examples 5 and 6. TABLE 4 Laminatedplate Comparative Comparative physical Example Example Example ExampleExample Example properties 16 17 18 19 5 6 Dielectric 4.0 4.1 3.9 4.14.1 4.5 constant (5 GHz) Dielectric 0.0035 0.0040 0.0050 0.0030 0.010.02 dissipation factor (5 GHz) Solder heat 120 sec. 120 sec. 120 sec.120 sec. 120 sec. 120 sec. resistance or more or more or more or more ormore or more (260° C.)

INDUSTRIAL APPLICABILITY

According to the present invention, there is provided a polyvinyl benzylcompound which provides a cured product having high heat resistance, lowwater absorption, a low dielectric constant and a low dielectricdissipation factor, a process for producing the polyvinyl benzylcompound, a curable resin composition comprising the polyvinyl benzylcompound, and a cured resin obtained by curing the composition.

Further, according to the present invention, there are provided asubstrate, a prepreg, and a metal foil having a resin all of which haveexcellent dielectric properties at a high frequency range, inparticular, a low dielectric dissipation factor, and high heatresistance.

1. A high-frequency substrate obtained by polymerizing and curing apolymerizable composition, wherein the polymerizable compositioncomprises a fluorene compound having at least one polymerizableunsaturated group in a molecule, except for a case where all of thepolymerizable unsaturated groups are vinylbenzyl groups.
 2. Ahigh-frequency substrate according to claim 1, wherein the fluorenecompound comprises one of: at least one of an allyl group and apropargyl group as a polymerizable unsaturated group; and at least onepolymerizable unsaturated group and a vinylbenzyl group.
 3. Ahigh-frequency substrate obtained by polymerizing and curing apolymerizable composition, wherein the polymerizable compositioncomprises an indene compound having at least one polymerizableunsaturated group in a molecule.
 4. A high-frequency substrate accordingto claim 3, wherein the polymerizable unsaturated group comprises atleast one group selected from a vinylbenzyl group, an allyl group, and apropargyl group.
 5. A high-frequency substrate obtained by polymerizingand curing a polymerizable composition, wherein the polymerizablecomposition comprises a fluorene compound having at least onepolymerizable unsaturated group in a molecule and an indene compoundhaving at least one polymerizable unsaturated group in a molecule.
 6. Ahigh-frequency substrate according to claim 2, wherein: the fluorenecompound comprises at least one compound represented by the followinggeneral formula 6; and the polymerizable composition comprises acompound obtained by reacting the fluorene compound, a halogen compoundhaving at least one polymerizable unsaturated group selected from thegroup consisting of a vinylbenzyl halide, an allyl halide, and apropargyl halide, and a dihalomethyl compound having 2 to 20 carbonatoms in the presence of an alkali:

wherein R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group.
 7. Ahigh-frequency substrate according to claim 4, wherein: the indenecompound comprises at least one compound represented by the followinggeneral formula 5; and the polymerizable composition comprises acompound obtained by reacting the indene compound, a halogen compoundhaving at least one polymerizable unsaturated group selected from thegroup consisting of a vinylbenzyl halide, an allyl halide, and apropargyl halide, and a dihalomethyl compound having 2 to 20 carbonatoms in the presence of an alkali:

wherein R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group.
 8. Ahigh-frequency substrate according to claim 5, wherein: the fluorenecompound comprises at least one compound represented by the followinggeneral formula 6; the indene compound comprises at least one compoundrepresented by the following general formula 5; and the polymerizablecomposition comprises a compound obtained by reacting the fluorenecompound, the indene compound, a halogen compound having at least onepolymerizable unsaturated group selected from the group consisting of avinylbenzyl halide, an allyl halide, and a propargyl halide, and adihalomethyl compound having 2 to 20 carbon atoms in the presence of analkali:

wherein R⁶ represents at least one group selected from the groupconsisting of a hydrogen atom, a halogen atom, an alkyl group, alkoxygroup, and thioalkoxy group each having 1 to 5 carbon atoms, which maybe the same or different, a thioaryloxy group, and an aryl group.
 9. Ahigh-frequency substrate according to any one of claims 6 to 8, whereinan equivalent ratio of a halomethyl group of the halogen compound havinga polymerizable unsaturated group to a halomethyl group of thedihalomethyl compound having 2 to 20 carbon atoms is 0.9/0.1 to 0.1/0.9.10. A high-frequency substrate according to claim 1, wherein thepolymerizable composition comprises a composition prepared by mixing afluorene compound having at least one polymerizable unsaturated group ina molecule and a compound which is copolymerizable with the fluorenecompound.
 11. A high-frequency substrate according to claim 3, whereinthe polymerizable composition comprises a composition prepared by mixingan indene compound having at least one polymerizable unsaturated groupin a molecule and a compound which is copolymerizable with the indenecompound.
 12. A prepreg obtained by impregnating a fiber material withthe polymerizable composition according to any one of claims 1, 3, 5, 6,7, 8, 10, and
 11. 13. A prepreg according to claim 12, wherein the fibermaterial comprises a glass cloth.
 14. A high-frequency substrateobtained by heating and pressurizing one of a single prepreg accordingto claim 12 and a prepreg laminate.
 15. A metal-lined high-frequencysubstrate obtained by placing a metal foil onto one of a single prepregaccording to claim 12 and a prepreg laminate, and heating andpressurizing the whole.
 16. A metal foil having a resin obtained byapplying the polymerizable composition according to any one of claims 1,3, 5, 6, 7, 8, 10, and 11 to a metal foil and integrating thepolymerizable composition and the metal foil.
 17. A multi-layer laminatesubstrate comprising: a cured product prepared by applying thepolymerizable composition according to any one of claims 1, 3, 5, 6, 7,8, 10, and 11 to a conductive layer, and polymerizing and curing thecomposition; and a conductive layer provided on the cured product.